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Martin Rees
OUR FINAL HOUR
A Scientist's Warning: How Terror, Error, and Environmental
Disaster Threaten Humankind's Future in This Century— On Earth
and Beyond
International Acclaim for Martin Rees's OUR FINAL HOUR
"[Rees's] cautionary tale comes as a useful counterbalance to some of
the overly optimistic books recently penned by scientists . . . Our Final Hour
neither worships nor condemns modern science, but it does offer a clear,
concise account of what may be our most urgent concerns in the 21st
century."
—The Globe and Mail (Toronto)
"Doomsday books have appeared for centuries. But Rees' book is
unique, and not only because of his fame as a Cambridge University
professor who is not prone to making scary public statements."
—San Francisco Chronicle
"One of the most provocative and unsettling books I have read for
many years . . . That a scientist so distinguished as Rees should air these
fierce anxieties is a sign that something is amiss."
—J. G. Ballard, The Daily Mail (London)
"Rees invites us to also consider developments that many of us
probably never thought about, including: Could environmental degradation
lead to a "war for water"? Could machines-designed plants crowd natural
plants out of the ecosystem? These ideas may inspire skepticism, but within
Rees' logic, they seem far from impossible. But Rees does not simply
outline his theories. Throughout, he repeatedly implies something else: We
can do something to help."
________________ Associated Press
OTHER BOOKS BY MART.N REES INCLUDE
Graves Fatal Attraction: Black Holes in the Umverse with Mitchell
Begelman
Before the Beginning: Our Universe and Others Just Six Numbers:
The Deep Forces
That Shape the Universe
Our Cosmic Habitat
BASIC
B
BOOKS
A Member of the Perseus Books Group
New York
Copyright © 2003 by Martin Rees
Published by Basic Books,
A Member of the Perseus Books Group
Hardback first published in 2003 by Basic Books Paperback first
published in 2004 by Basic Books
All rights reserved. Printed in the United States of America. No part
of this book may be reproduced in any manner whatsoever without written
permission except in the case of brief quotations embodied in critical
articles and reviews. For information, address Basic Books, 387 Park
Avenue South, New York, NY 10016
Books published by Basic Books are available at special discounts
for bulk purchases in the United States by corporations, institutions, and
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Markets Department at the Perseus Books Group, 11 Cambridge Center,
Cambridge, MA 02142, or call (617) 252-5298, (800) 255-1514 or e-mail
special.markets@perseusbooks.com.
Library of Congress Cataloging-in-Publication Data
Rees, Martin J., 1942-
Our final hour: A scientist's warning: How terror, error, and
environmental disaster threaten humankind's future in this century—
on Earth and beyond / Martin Rees.
p. cm.
Includes bibliographical references and index.
ISBN 0-465-0682-6 (he); ISBN 0-465-06863-4 (pbk)
1. Twenty-first century—Forecasts. 2. Disasters—Forecasts.
3. End of the world. 1. Title.
CB161.R38 2003
3O3.49'oo'o5—dc21 2003000301
Design by Jane Raese Text set in 11 point Janson
04 05 06 / 10 9 8 7 6 5 4 3 2 1
CONTENTS PROLOGUE ............................................................................................................................................................................. 72. TECHNOLOGY SHOCK ................................................................................................................................................... 15A Human or Posthuman Future? ............................................................................................................................................. 253. THE DOOMSDAY CLOCK .............................................................................................................................................. 334. POST-2000 THREATS Terror and Error .......................................................................................................................... 495. PERPETRATORS AND PALLIATIVES .......................................................................................................................... 696. SLOWING SCIENCE DOWN? ......................................................................................................................................... 797 BASELINE NATURAL HAZARDS .................................................................................................................................. 95Asteroid Impacts ..................................................................................................................................................................... 95A Low Risk, but Not Negligible ............................................................................................................................................. 98Reducing the Risk? ............................................................................................................................................................... 1008. HUMAN THREATS TO EARTH .................................................................................................................................... 1049. EXTREME RISKS ........................................................................................................................................................... 116Our "Final" Experiment? ...................................................................................................................................................... 12011.THE END OF SCIENCE? ............................................................................................................................................... 14112. DOES OUR FATE HAVE COSMIC SIGNIFICANCE? ............................................................................................... 15613. BEYOND EARTH ......................................................................................................................................................... 168NOTES ................................................................................................................................................................................. 185
PREFACE
SCIENCE IS ADVANCING FASTER THAN EVER, and on a broader front:
bio-, cyber- and nanotechnology all offer exhilarating prospects; so does the
exploration of space. But there is a dark side: new science can have
unintended consequences; it empowers individuals to perpetrate acts of
megaterror; even innocent errors could be catastrophic. The "downside"
from twenty-first century technology could be graver and more intractable
than the threat of nuclear devastation that we have faced for decades. And
human-induced pressures on the global environment may engender higher
risks than the age-old hazards of earthquakes, eruptions, and asteroid
impacts.
This book, though short, ranges widely. Separate chapters can be
read almost independently: they deal with the arms race, novel technologies,
environmental crises, the scope and limits of scientific invention, and
prospects for life beyond the Earth. I've benefited from discussions with
many specialists; some of them will, however, find my cursory
presentation differently slanted from their personal assessment. But these
are controversial themes, as indeed are all "scenarios" for the long-term
future.
If nothing else, I hope to stimulate discussion on how to
guard (as far as is feasible) against the worst risks, while deploying
new knowledge optimally for human benefit. Scientists and technologists
have special obligations. But this perspective should strengthen everyone's
concern, in our interlinked world, to focus public policies on communities
who feel aggrieved or are most vulnerable.
I thank John Brockman for encouraging me to write the book. I'm
grateful to him and to Elizabeth Maguire for being so patient, and to
Christine Marra and her colleagues for their efficient and expeditious efforts
to get it into print.
OUR FINAL HOUR
PROLOGUE
THE TWENTIETH CENTURY BROUGHT US THE BOMB, and the nuclear
threat will never leave us; the short-term threat from terrorism is high on the
public and political agenda; inequalities in wealth and welfare get ever
wider. My primary aim is not to add to the burgeoning literature on these
challenging themes, but to focus on twenty-first century hazards, currently
less familiar, that could threaten humanity and the global environment still
more.
Some of these new threats are already upon us; others are still
conjectural. Populations could be wiped out by lethal "engineered" airborne
viruses; human character may be changed by new techniques far more
targeted and effective than the nostrums and drugs familiar today; we may
even one day be threatened by rogue nanomachines that replicate
catastrophically, or by superintelligent computers.
Other novel risks cannot be completely excluded. Experiments that
crash atoms together with immense force could start a chain reaction that
erodes everything on Earth; the experiments could even tear the fabric of
space itself, an ultimate "Doomsday" catastrophe whose fallout spreads at
the speed of light to engulf the entire universe. These latter scenarios may
be exceedingly unlikely, but they raise in extreme form the issue of who
should decide, and how, whether to proceed with experiments that have a
genuine scientific purpose (and could conceivably offer practical benefits),
but that pose a very tiny risk of an utterly calamitous outcome.
We still live, as all our ancestors have done, under the threat of
disasters that could cause worldwide devastation: volcanic supereruptions
and major asteroid impacts, for instance. Natural catastrophes on this global
scale are fortunately so infrequent, and therefore so unlikely to occur within
our lifetime, that they do not preoccupy our thoughts, nor give most of us
sleepless nights. But such catastrophes are now augmented by other
environmental risks that we are bringing upon ourselves, risks that cannot
be dismissed as so improbable.
During the Cold War years, the main threat looming over us was an
all-out thermonuclear exchange, triggered by an escalating superpower
confrontation. That threat was apparently averted. But many experts—
indeed, some who themselves controlled policy during those years—
believed that we were lucky; some thought that the cumulative risk of
Armageddon over that period was as much as fifty percent. The immediate
danger of all-out nuclear war has receded. But there is a growing threat of
nuclear weapons being used sooner or later somewhere in the world.
Nuclear weapons can be dismantled, but they cannot be un-invented.
The threat is ineradicable, and could be resurgent in the twenty-first
century: we cannot rule out a realignment that would lead to standoffs as
dangerous as the Cold War rivalry, deploying even bigger arsenals. And
even a threat that seems, year by year, a modest one mounts up if it persists
for decades. But the nuclear threat will be overshadowed by others that
could be as destructive, and far less controllable. These may come not
primarily from national governments, not even from "rogue states," but
from individuals or small groups with access to ever more advanced
technology. There are alarmingly many ways in which individuals will be
able to trigger catastrophe.
The strategists of the nuclear age formulated a doctrine of deterrence
by "mutually assured destruction" (with the singularly appropriate acronym
MAD). To clarify this concept, real-life Dr. Strangeloves envisaged a
hypothetical "Doomsday machine," an ultimate deterrent too terrible to be
unleashed by any political leader who was one hundred percent rational.
Later in this century, scientists might be able to create a real nonnuclear
Doomsday machine. Conceivably, ordinary citizens could command the
destructive capacity that in the twentieth century was the frightening
prerogative of the handful of individuals who held the reins of power in
states with nuclear weapons. If there were millions of independent fingers
on the button of a Doomsday machine, then one person's act of irrationality,
or even one person's error, could do us all in.
Such an extreme situation is perhaps so unstable that it could never
be reached, just as a very tall house of cards, though feasible in theory,
could never be built. Long before individuals acquire a "Doomsday"
potential—indeed, perhaps within a decade—some will acquire the power
to trigger, at unpredictable times, events on the scale of the worst present-
day terrorist outrages. An organised network of Al Qaeda-type terrorists
would not be required: just a fanatic or social misfit with the mindset of
those who now design computer viruses. There are people with such
propensities in every country— very few, to be sure, but bio- and cyber-
technologies will become so powerful that even one could well be too
many.
4
By mid-century, societies and nations may have drastically
realigned; people may live very differently, survive to a far greater age,
and have different attitudes from those of the present (maybe modified by
medication, chip implants, and so forth). But one thing is unlikely to
change: individuals will make mistakes, and there will be a risk of
malign actions by embittered loners and dissident groups. Advanced
technology will offer new instruments for creating terror and devastation;
instant universal communications will amplify their societal impact.
Catastrophes could arise, even more worryingly, simply from technical
misadventure. Disastrous accidents (for instance, the unintended creation
or release of a noxious fast-spreading pathogen, or a devastating software
error) are possible even in well-regulated institutions. As the threats
become graver, and the possible perpetrators more numerous, disruption
may become so pervasive that society corrodes and regresses. There is a
longer-term risk even to humanity itself.
Science is emphatically not, as some have claimed, approaching its
end; it is surging ahead at an accelerating rate. We are still flummoxed
about the bedrock nature of physical reality, and the complexities of life,
the brain, and the cosmos. New discoveries, illuminating all these
mysteries, will engender benign applications; but will also pose new ethical
dilemmas and bring new hazards. How will we balance the multifarious
prospective benefits from genetics, robotics, or nanotechnology against the
risk (albeit smaller) of triggering utter disaster?
My special scientific interest is cosmology: researching our en-
vironment in the widest conceivable perspective. This might seem an
incongruous viewpoint from which to focus on practical terrestrial issues: in
the words of Gregory Benford, a fiction writer who is also an astrophysicist,
study of the "grand gyre of worlds.. . imbues, and perhaps afflicts,
astronomers with a perception of how like mayflies we are." But few
scientists are unworldly enough to fit Benford's description: a
preoccupation with near-infinite spaces doesn't make cosmologists
especially "philosophical" in coping with everyday life; nor are they less
engaged with the issues confronting us here on the ground, today and
tomorrow. My subjective attitude was better expressed by the
mathematician and philosopher Frank Ramsey, a member of the same
College in Cambridge (King's) to which I now belong: "I don't feel the least
humble before the vastness of the heavens. The stars may be large, but they
cannot think or love; and these are qualities which impress me far more
than size does. My picture of the world is drawn in perspective, and not
like a model drawn to scale. The foreground is occupied by human beings,
and the stars are all as small as three penny bits." A cosmic perspective
actually strengthens our concerns about what happens here and now,
because it offers a vision of just how prodigious life's future potential
could be. Earth's biosphere is the outcome of more than four billion
years of Darwinian selection: the stupendous time spans of the evolu-
tionary past are now part of common culture. But life's future could be
more prolonged than its past. In the aeons that lie ahead, even more
marvellous diversity could emerge, on and beyond Earth. The unfolding
of intelligence and complexity could still be near its cosmic beginnings.
A memorable early photograph taken from space depicted
"Earthrise" as viewed from a spacecraft orbiting the Moon. Our habitat of
land, oceans, and clouds was revealed as a thin delicate glaze, its beauty
and vulnerability contrasting with the stark and sterile moonscape on
which the astronauts left their footprints. We have had these distant
images of the entire Earth only for the last four decades. But our planet
has existed for more than a hundred million times longer than this. What
transrormations did it undergo during this cosmic time span?
6
About 4.5 billion years ago our Sun condensed from a cosmic cloud;
it was then encircled by a swirling disk of gas. Dust in this disk
agglomerated into a swarm of orbiting rocks, which then coalesced to form
the planets. One of these became our Earth: the "third rock from the Sun."
The young Earth was buffeted by collisions with other bodies, some
almost as large as the planets themselves: one such impact gouged out
enough molten rock to make the Moon. Conditions quietened and Earth
cooled. The next transformations distinctive enough to be seen by a
faraway observer would have been very gradual. Over a prolonged time
span, more than a billion years, oxygen accumulated in Earth's atmosphere,
a consequence of the first unicellular life. Thereafter, there were slow
changes in the biosphere, and in the shape of the land masses as the
continents drifted. The ice cover waxed and waned: there might even have
been episodes when the entire Earth froze over, appearing white rather
than pale blue.
The only abrupt worldwide changes were triggered by major asteroid
impacts or volcanic supereruptions. Occasional incidents like these would
have flung so much debris into the stratosphere that for several years, until
all the dust and aerosols settled again, Earth looked dark grey, rather than
bluish white, and no sunlight penetrated down to land or ocean. Apart from
these brief traumas, nothing happened suddenly: successions of new species
emerged, evolved, and became extinct on geological time scales of millions
of years.
But in just a tiny sliver of Earth's history—the last one-millionth
part, a few thousand years—the patterns of vegetation altered much faster
than before. This signalled the start of agriculture: the imprint on the
terrain of a population of humans, empowered by tools. The pace of change
accelerated as human populations rose. But then quite different transforma-
tions were perceptible, and these were even more abrupt.
Within fifty years, little more than one hundredth of a milion’’th
of Earth's age, the amount of carbon dioxide in the atmosphere, which
over most of Earth's history had been slowly falling began to rise
anomalously fast. The planet became an
intense emitter of radio waves (the total output from all TV,
cellphone, and radar transmissions).
And something else happened, unprecedented in Earth's 4.5 billion
year history: metallic objects—albeit very small ones, a few tonnes at
most—left the planet's surface and escaped the biosphere completely. Some
were propelled into orbits around Earth; some journeyed to the Moon and
planets; a few even followed a trajectory that would take them deep into
interstellar space, leaving the solar system for ever.
A race of scientifically advanced extraterrestrials watching our solar
system could confidently predict that Earth would face doom in another
six billion years, when the Sun, in its death throes, swells up into a "red
giant" and vaporises everything remaining on our planet's surface. But could
they have predicted this unprecedented spasm less than halfway through
Earth's life—these human-induced alterations occupying, overall, less than a
millionth of our planet's elapsed lifetime and seemingly occurring with
runaway speed?
If they continued to keep watch, what might these hypothetical aliens
witness in the next hundred years? Will a final squeal be followed by silence?
Or will the planet itself stabilise? And will some of the small metallic
objects launched from Earth spawn new oases of life elsewhere in the solar
system, eventu-a% extending their influences, via exotic life, machines, or
sophisticated signals, far beyond the solar system, creating an expanding
"green sphere" that eventually pervades the entire Galaxy?
It may not be absurd hyperbole—indeed, it may not even be an
overtatement—to assert that the most crucial location in space and time
(apart from the big bang itself) could be here and now. I think the odds are
no better than fifty-fifty that our present civilisation on Earth will survive to
the end of the present century. Our choices and actions could ensure the
perpetual future of life (not just on Earth, but perhaps far beyond it, too).
Or in contrast, through malign intent, or through misadventure, twenty-first
century technology could jeopardise life's potential, foreclosing its human
and posthuman future. What happens here on Earth, in this century, could
conceivably make the difference between a near eternity filled with ever
more complex and subtle forms of life and one filled with nothing but base
matter.
2. TECHNOLOGY SHOCK
Twenty-first century science may alter human beings themselves—
not just how they live. A superintelligent machine could be the last invention
humans ever make.
IN THE PAST CENTURY, there were more changes than in the
previous thousand years. The new century will see changes that will dwarf
those of the last" This was an often expressed sentiment in the years 2000
and 2001, at the dawn of the new millennium; but these words actually date
from more than one hundred years ago, and refer to the nineteenth and
twentieth centuries, not the twentieth and twenty-first. They are from a 1902
lecture entitled "Discovery of the Future" presented by the young H.G.
Wells at the Royal Institution in London. By the end of nineteenth century,
Darwin and the geologists had already delineated, in crude outline, how
Earth and biosphere had evolved. Earth's full age was still not recognised
but estimates had risen to hundreds of millions of years. Wells himself was
taught these ideas, still novel and inflammatory at that time, by Darwin's
greatest advocate and propagandist, Ɍ.ɇ. Huxley.
Wells's lecture was mainly in visionary mode. "Humanity," he said,
"has come some way, and the distance we have travelled gives us some
earnest of the way we have to go. All the past is but the beginning of a
beginning; all that the human mind has accomplished is but the dream
before the awakening." His rather purple prose still resonates a hundred
years later. Our scientific understanding—of atoms, life and the cosmos—
has burgeoned in a fashion that not even he conceived: certainly Wells was
right in predicting that the twentieth century would see more changes than
the previous thousand years. Spinoffs from novel discoveries have
transformed our world and our lives. The amazing technical innovations
would surely have elated him, as would the prospects for the coming
decades.
But Wells wasn't a naive optimist. His lecture highlighted the risk of
global disaster: "It is impossible to show why certain things should not
utterly destroy and end the human race and story; why night should not
presently come down and make all our dreams and efforts vain . . .
something from space, or pestilence, or some great disease of the
atmosphere, some trailing cometary poison, some great emanation of
vapour from the interior of the Earth, or new animals to prey on us, or some
drug or wrecking madness in the mind of man." In his later years, Wells
became more pessimistic, especially in his final book, The Mind at the End
of its Tether. His near despair about the "downside" of science might have
deepened were he writing today-Humans already have the wherewithal to
destroy their civilization by nuclear war: in the new century, they are
acquiring bio1ogical expertise that could be equally lethal; our integrated
society will become more vulnerable to cyber-risks; and human pressure
on the environment is building up dangerously. The tension between
benign and damaging spinoffs from new discoveries and the threats
posed by the Promethean power science gives us, are disquietingly real,
and sharpening up.
Wells's audience at the Royal Institution would have already known
him as the author of The Time Machine. In this classic story the chrononaut
gently eased the throttle of his machine forward: "night came like the
turning out of a light, and in another moment came tomorrow." As he sped
up "the palpitation of night and day merged into one continuous greyness.
. . . I travelled, stopping ever and again, in great strides of a thousand
years or more, drawn on by the mystery of the Earth's fate, watching with
a strange fascination the sun grow larger and duller in the westward sky,
and the life of the old Earth ebb away." He encounters an era where the
human species has split into two: the effete and infantile Eloi, and the
brutish underground Morlocks who exploit them. He ends up thirty million
years hence, in a world where all familiar forms of life have become extinct.
He then returns to the present, bringing strange plants as evidence of his
trip.
In Wells's story it takes eight hundred thousand years for humans to
divide into two subspecies, a time span that accords with modern ideas of
how long it took for humanity to emerge via natural selection. (Evidence for
our earliest hominoid ancestors extends back for four million years; it is
about forty thousand years since "modern" humans superseded the
Neandertals.) But in the new century, changes in human bodies and brains
won't be restricted to the pace of Darwinian selection, nor even to that of
selective breeding. Genetic engineering and biotechnology, if widely
practiced, could transmogrify human-Physique and mentality far faster
than Wells foresaw.
Indeed, Lee Silver, in his book Remaking Eden, conjectures that it
could take only a few generations for humanity to divide into two species: if
the technology enabling parents to "design" genetically advantaged
children were available only to the wealthy, there would be a widening
divergence between the "GenRich" and the "Naturals." Nongenetic changes
could be even more sudden, transforming humanity's mental character in
less than a generation, as quickly as new drugs can be developed and
marketed. The fundamentals of humanity, essentially unaltered throughout
recorded history, could start to be transformed within this century.
Failed Forecasts
I recently found in an antiquarian bookshop some science magazines,
dating from the 1920s, with imaginative depictions of the future. The then-
futuristic aeroplanes had rows of wings one above the other; the artist had
surmised that since biplanes then seemed an advance on monoplanes, it
would be still more "advanced" to stack wings like a Venetian blind.
Extrapolation can be misleading. Moreover, straightforward projections of
present trends will miss the most revolutionary innovations: the
qualitatively new things that really change the world.
Even four hundred years ago, Francis Bacon emphasised that the most
important advances are the least predictable. Three ancient discoveries
especially astonished him: gunpowder, silk, and the mariner's compass. In
Novum Organum he writes, "these things ... were not discovered by
philosophy or the arts of reason, but by chance and occasion," They are
"different ʋ kind," so that "no preconceived notion could possibly have con-
duced to their discovery." It was Bacon's belief that "there are still many
things of excellent use stored up in the lap of nature
13
Having nothing in them kindred or parallel to what is already
discovering… lyiing quite out of the path of imagination." X-rays discovered
in 1895, must have seemed fully as magical to Well as the compass did to
Bacon. Though of manifest benefit they couldn't possibly have been
planned for. A research proposal to make flesh appear transparent wouldn't
have been funded, and even if it had been, the research surely wouldn't
have led to the X ray. And the big discoveries have continued to take us
unawares. Few managed to predict the inventions that transformed the world
in the second half of the twentieth century. In 1937 the US National
Academy of Sciences organised a study aimed at predicting breakthroughs;
its report makes salutary reading for technological forecasters today. It came
up with some wise assessments about agriculture, about synthetic gasoline,
and synthetic rubber. But what is more remarkable is the things it missed.
No nuclear energy, no antibiotics (though this was eight years after
Alexander Fleming had discovered penicillin), no jet aircraft, no rocketry
nor any use of space, no computers; certainly no transistors. The committee
overlooked the technologies that actually dominated the second half of the
twentieth century. Still less could they predict the social and political
transformations that occurred during that time.
Scientists are often blind to the ramifications of even their own
discoveries. Ernest Rutherford, the greatest nuclear physicist of his time,
famously dismissed as "moonshine" the practical relevance of nuclear
energy. The pioneers of radio regarded wireless transmission as a substitute
for the telegraph, rather as a means for "one-to-many" broadcasting.
Neither the computer designer and mathematician John von Neumann nor
the IBM founder Thomas J. Watson envisaged need for more then a few
computing machines in the entire a country. Today ubiquitus mobile
phones and palmtop computers would amaze anyone from a century ago;
they are exemplars of Arthur C. Clarke's dictum that any sufficiently ad-
vanced technology is indistinguishable from magic. So what might happen
in the new century that would be "magic" to us?
Forecasters have generally failed dismally to foresee the drastic
changes brought about by completely unpredictable discoveries. In
contrast, incremental change is often slower than forecasters expect,
certainly far slower than is technically possible. Few have been as
prescient as Clarke, but we will certainly have to wait until far later than
2001 before there are large space colonies or lunar bases. And the
technology of civil aviation has stagnated, almost in the way that manned
space flight has. We could have had hypersonic planes by now, but—
basically for economic and environmental reasons—we don't: we cross
the Atlantic in jets that have had basically similar performance for the last
forty-five years, and are likely to for the next twenty. What has changed is
the volume of traffic. Long-distance air travel has been transformed into
an affordable mass market. Of course, there have been technical
improvements, for instance in computerised control, and the precise
positioning offered by global positioning system (GPS) satellites; for
passengers the most conspicuous changes are in the sophistication of the
gad-getry that provides on-board entertainment. Similarly, we drive cars
that improve only incrementally over the decades. Transport technology in
general has developed more slowly than many forecasters expected.
On the other hand, Clarke and most others were taken unawares by
the speed with which personal computers proliferated and improved, and
by spinoffs such as the Internet. The density with which circuits are
etched on computer microchips has now been doubling every eighteen
months for nearly thirty years in accordance with the famous "law" put
forward by Gordon Moore, cofounder of Intel Corporation. In
consequence,
15
there is far more processing power in a computer-game console
than was available to the Apollo astronauts when they landed on the
Moon. My Cambridge colleague George Efstathiou, who simulates on a
computer how galaxies form and evolve, can now repeat, on his laptop
during his lunch break, calculations that took months on one of the
world's fastest supercomputers then available when he first did them in
1980. Soon we will not merely have mobile phones, but high-bandwidth
communication with everyone else, and instant access to all recorded
knowledge. And the genomics revolution—a dominant feature of the early
twenty-first century—is accelerating: when the great project to map the
human genome began, few expected that it would be essentially
completed by now.
Francis Bacon contrasted his three "magical" discoveries with the
invention of printing, which "has nothing in it which is not open and
generally obvious. . . when it had been made, it seems incredible that it
should have escaped notice so long." Most inventions emerge, as printing
did, by Bacon's second route: "from the transferring, composition, and
application of [things] already known." The artefacts and gadgets familiar
in everyday life are generally the outcome of a continuing trail of
incremental improvement. But there can still be revolutionary
innovations, despite the immense scientific infrastructure that was quite
lacking in earlier centuries. Indeed, the lengthening frontiers of
knowledge increase the chance of some remarkable surprises.
Faster Forward?
Over an entire century, we cannot set limits on what science can
achieve, so we should leave our minds open, or at least ajar, to concepts
that now seem on the wilder shores of speculative
16
thought. Superhuman robots are widely predicted for mid-century.
Even more astonishing advances could eventually stem from fundamentally
new concepts in basic science that haven't yet even been envisioned and
which we as yet have no vocabulary to describe. It is impossible to make
firm projections that entail huge extrapolations of present knowledge
Ray Kurzweil, guru of "artificial intelligence" and author of The Age
of Spiritual Machines, claims that the twenty-first century will see "20,000
years of progress at today's rate." That is just a rhetorical claim, of course,
since "progress" can be quantified only within limited domains.
There are physical limits to how finely silicon microchips can be
etched by present techniques, for the same reason that there are limits to the
sharpness of the images that microscopes or telescopes can give us. But
new methods are already being developed that can print circuits on a much
finer scale, so "Moore's law" need not level off. Even within ten years,
wrist-watch-size computers will link us to an advanced internet and to the
global positioning system. Looking further ahead, quite different
techniques—tiny crisscrossing optical beams, not involving chip circuits at
all—may increase computing power still further.
Miniaturisation, though already amazing, is very far indeed from its
theoretical limits. Each tiny circuit-element of a silicon chip contains
billions of atoms: such a circuit is exceedingly large and "coarse" compared
to the smallest circuits that could in principle exist. These would have
dimensions of only a nanometer—a billionth of a meter, rather than the
micron (millionth of a meter) scale on which present-day chips are etched.
One long-term hope is to assemble nanostructures and circuits "bottom up"
by sticking single atoms and molecules together. This is how living
organisms grow and develop. And it is how nature's "computers" are made:
an insect's brain has
17
about the same processing power as a powerful present-day
computer.
The evangelists of nanotechnology envisage an "assembler" that
could grab single atoms, shifting them around and assembling them one by
one into machines with components no bigger than molecules. These
techniques will allow computer processors to be a thousand times smaller,
and information to be stored in memories a billion times more compact than
the best we have today. Indeed, human brains may be augmented by
implants of computers. Nanomachines could have as intricate a molecular
structure as viruses and living cells, and display even more variety; they
could carry out manufacturing tasks; they could crawl around inside our
bodies observing and taking measurements, or even performing
microsurgery.
Nanotechnology could extend Moore's law for up to thirty further
years; by that time, computers would match the processing power of a
human brain. And all human beings could by then be bathed in a cyberspace
that allows instant communication with one another, not just in speech and
vision but via elaborate virtual reality.
The robotics pioneer Hans Moravec believes that machines will
attain human-level intelligence and may even "take over." For this to
happen, processing power is not enough: the computers will need sensors
that enable them to see and hear as well as we do, and the software to
process and interpret what their sensors tell them. Advances in software
have been far slower than in hardware: computers still can't match the
facility of even a three-year-old child in recognising and manipulating solid
objects. Perhaps more will be achieved by trying to "reverse-engineer" the
human brain, rather than by just speeding UP and compacting traditional
processors. Once computers can observe and interpret their environment as
adeptly as we do through our eyes and other sense organs, their far faster
thinking
18
and responses could give them an advantage over us. Then they will
truly be perceived as intelligent beings, to which (or to whom) we can
relate, at least in some respects, as we to other people. Ethical issues then
arise. We generally accept an obligation to ensure that other human beings
(and indeed at least some animal species) can fulfil their "natural" potential.
Will we have the same duty to sophisticated robots, our own creations?
Should we feel obligated to foster their welfare, and guilty if they are
underemployed, frustrated, or bored?
A Human or Posthuman Future?
These projections assume that our descendants remain distinctively
"human." But human character and physique will soon themselves be
malleable. Implants into our brain (and perhaps new drugs as well) could
vastly enhance some aspects of human intellectual powers: our logical or
mathematical skills, and perhaps even our creativity. We may be able to
"plug in" extra memory, or learn by direct input into the brain (the injection
of an "instant Ph.D."?). John Sulston, a leader of the Human Genome
Project, speculates on further implications: "How much non-biological
hardware can we hook up to a human body and still call it human? ... A
little more memory, perhaps? More processing power? Why not? And if so,
perhaps a kind of immortality is just around the corner."
A further step would be to reverse-engineer human brains in enough
detail to be able to download thoughts and memories into a machine, or
reconstruct them artificially. Humans could then transcend biology by
merging with computers, maybe losing their individuality and evolving into
a common consciousness. If present technical trends proceeded unimpeded,
then we should not dismiss Moravec's belief that some people now
living could attain immortality—in the sense of having a life span
that is not constrained by their present bodies. Those who seek this kind of
everlasting life will need to abandon their bodies and have their brains
downloaded into silicon hardware. In old-style spiritualist parlance, they
would "go over to the other side."
A superintelligent machine could be the last invention that humans
need ever make. Once machines have surpassed human intelligence, they
could themselves design and assemble a new generation of even more
intelligent ones. This could then repeat itself, with technology racing
towards a cusp, or "singularity," at which the rate of innovation runs away
towards infinity. (The Californian futurologist Vernor Vinge was the first to
use the term "singularity" in this apocalyptic context.) It is impossible to
predict what the world might be like after the occurrence of such a
"singularity." Even the constraints based on currently understood physical
laws may be insecure. Some of the "staples" of speculative science that
flummox physicists today— time travel, space warps, and the like—may be
harnessed by the new machines, transforming the world physically as well.
Kurzweil and Vinge are of course on (or even beyond) the visionary
fringe, where scientific prediction meets science fiction. Belief in the
"singularity" relates to mainstream futurology rather as the millenarian hope
of "Rapture"—being physically plucked up into the Heavens at an imminent
Last Day—relates to mainstream Christianity.
The Steady Backdrop
Information systems and biotechnology can surge ahead rapidly
because (unlike, for instance, traditional forms of power generation and
transport infrastructure) they do not depend on
19
20
huge facilities that take years to construct and have to be operated for
decades. But not everything is as mutable and transient as electronic
hardware.
Barring some calamitous destruction—or unless there were indeed a
technological surge towards a "singularity," after which superrobots could
transform the world more drastically than we can now conceive—there are
limits to how fast our terrestrial environment could alter. We will still have
roads and (probably) railways, but these may be supplemented by novel
means of travel (for example, GPS systems could allow automated
collision-free journeys by land or air). The developing world could, on
optimistic scenarios, acquire a new twenty-first-century infrastructure,
unencumbered by the legacy of the past. But some limits are set by energy
and resources: supersonic travel is unlikely to become routine for most of
the world's population, unless some radically new plane design or engine is
invented. Much travel will, however, become superfluous, superseded by
telecommunication and virtual reality.
What about exploitation of space (perhaps using novel propulsion
systems)? Robotics and miniaturisation are weakening the short-term
practical case for manned space flight. In the coming decades, swarms of
miniaturised satellites will orbit Earth; intricately instrumented unmanned
probes will roam and explore throughout the solar system; and robotic
fabricators will assemble large structures, perhaps extracting raw materials
from the Moon or from asteroids. Within fifty years, if our civilisation
escapes disastrous setbacks in the meantime, there could be a vibrant
programme of human space exploration, though it is likely to be led by
entrepreneurs and adventurers rather than by governments.
Even if there is an expanding human presence in space, it will
involve only a trivial fraction of humanity. Nowhere away from Earth offers
a habitat that is even as clement as the Antarctic or the deep ocean bed;
nonetheless, space may offer the backdrop for enthusiastic explorers and
pioneers, who may eventually set up self-sustained social groups away from
Earth. By the end of the century, such communities could have been
established— on the Moon, on Mars, or freely floating in space—either as
refuges, or in a spirit of exploration. Whether this happens, and how, could
be crucial to posthuman evolution, and indeed to the fate of intelligent life
in future centuries. Although it would be little consolation to those on Earth,
life would have "tunnelled through" its era of maximum jeopardy: no terres-
trial catastrophe could thereafter quench life's long-term cosmic potential.
The Real World: Longer Horizons
Techno-forecasters, their attitudes moulded by the social and
political environment of the West Coast of the United States, where so
many such people are congregated, tend to envisage that changes proceed
untrammelled, in a social system supportive of innovations and that
consumerist motivations dominate other ideologies. These presumptions
may be as unwarranted as it would have been to downplay the role of
religion in international affairs, or to predict that sub-Saharan Africa would
have advanced steadily since the 1970s rather than regressing further into
destitution. Unpredictable social and political developments add extra
dimensions of uncertainty. Indeed, a main theme of this book is that
technical advances will in themselves render society more vulnerable to
disruption.
But even if disruption were no worse than it is today, these forecasts
do little more than set the "envelope" of what might be possible: the gap
between what is technically possible and
21
22
what will actually happen is going to widen. Some innovations just
don't attract enough economic or social demand: just as supersonic flight
and manned space flight stagnated after the 1970s, today (in 2002) the
potentialities of broadband (G3) technology are being taken up rather
slowly because few people want to surf the Internet or watch movies from
their mobile phones.
For biotechnologies, the inhibition will be more ethical than
economic. If there were no regulations to rein back the application of
genetic techniques, the physique and mentality of human beings could
morph within a few generations. Futurists like Freeman Dyson speculate
that within a few centuries, Homo sapiens may have diversified into
numerous subspecies, adapting to a variety of habitats beyond Earth.
Economic decisions generally discount into insignificance what may
happen more than twenty years from now: commercial ventures are not
worthwhile unless they pay off far sooner than that, especially when
obsolescence is rapid. Government decisions are often as short-term as the
next election. But sometimes—in energy policy, for example—the horizon
extends to fifty years. Some economists are trying to provide incentives for
longer-term planning and prudent conservation by putting a monetary value
on a country's natural resources, thereby rendering explicit in a nation's
balance sheet the cost of depleting them. The debates about global warming
that led to the Kyoto Protocol take cognisance of what might happen one or
two centuries ahead: the consensus is that governments should take
preemptive actions now, in the putative interest of our twenty-second-
century descendants (though whether these actions will actually be
implemented is still unclear).
There is one context in which official public policy looks even
further ahead, not just for hundreds but for thousands of years: the disposal
of radioactive waste from nuclear power stations. Some of this waste will
remain toxic for many millennia; both in the UK and the US, the
specification for underground depositories demands that hazardous
materials should remain sealed off—with no leakage via groundwater, or
through fissures opened up by earthquakes—for at least ten thousand years.
These geological requirements, imposed by the US Environmental
Protection Agency, were important factors in the choice of a Nevada
location, deep underground below Yucca Mountain, for the US's national
waste dump.
The prolonged debates on radioactive waste disposal have had at
least one benefit: they have generated interest and concern about how our
present-day actions resonate through several millennia—time spans still
infinitesimal, of course, compared to the future of Earth, but nonetheless far
beyond the horizon of most other planners and decision-makers. The US
Department of Energy even convened an interdisciplinary group of
academics to discuss how best to design a message that could be understood
by human beings (if any should exist) several millennia hence. Warnings
unambiguous and universal enough to bridge any conceivable culture gap
could be genuinely important in alerting our remote descendants to hidden
dangers like radioactive waste depositories.
The Long Now Foundation, an initiative promoted by Danny Hillis
(best known as inventor of the "Connection Machine," an early massively
parallel processing computer), aims to promote long-term thinking by
constructing a large ultra-durable clock that would record the passage of
several millennia. Stewart Brand, in his book The Clock of the Long Now,
discusses how to optimise the content of libraries, time capsules, and other
enduring artefacts that could help to raise our gaze towards longer time
horizons.
Even if changes proceed no faster than in the last few centuries, there
will certainly be a "turnover" in cultures and political institutions within a
single millennium. A catastrophic collapse of civilization could destroy
continuity, creating a gap as
23
24
wide as the cultural chasm that we would now experience with a
remote Amazonian tribe. In Walter M. Miller Jr.'s novel A Canticle for
Leibowitz, North America reverts to a medieval state after a devastating
nuclear war. The Catholic Church is the only institution to survive, and
generations of priests attempt, for several centuries, to reconstruct prewar
knowledge and technology from fragmentary records and relics. James
Lovelock (best known as the originator of the "Gaia" concept, likening the
biosphere to a self-regulating organism) urges compilation of a "start up
manual for civilisation," copies of which should be dispersed widely
enough to ensure that some survive almost any eventuality: it would
describe techniques of agriculture, from selective breeding to modern
genetics, and cover other technologies similarly.
By making us aware of longer time horizons, the proponents of the
Long Now remind us that the welfare of far-future generations should not
be jeopardised by imprudent policies today. But they are perhaps
downplaying the qualitatively new consequences of computers and
biotechnology. Optimists believe that these will lead to the transformations
discussed in this chapter; realists accept that these advances will open up
new peril. Prospects are so volatile that mankind might not even persist
beyond a century—much less a millennium—unless all nations adopt low-
risk and sustainable policies based on present technology. But that would
require an infeasible brake on new discoveries and inventions. A more
realistic forecast is that society's survival on Earth will, within this century,
be exposed to new challenges so threatening that the radioactivity level in
Nevada thousands of years from now will seem supremely irrelevant. In-
deed, the next chapter suggests that we have been lucky to survive the last
fifty years without catastrophe.
3. THE DOOMSDAY CLOCK
Have We Been Lucky to Survive This Long?
The Cold War exposed us to graver risks than most would
knowingly have accepted. The danger of nuclear devastation still
looms, but threats stemming from new science are even more
intractable.
THROUGHOUT MOST OF HUMAN HISTORY the worst disasters have
been inflicted by environmental forces—floods, earthquakes, volcanoes and
hurricanes—and by pestilence. But the greatest catastrophes of the
twentieth century were directly induced by human agency: one estimate
suggests that in the two world wars and their aftermath, 187 million
perished by war massacre, persecution, or policy-induced famine. The
25
26
twentieth century was perhaps the first during which more were
killed by war and totalitarian regimes than by natural disasters. These man-
made catastrophes were, however, played out against a backdrop of
improving well-being, and not just in privileged countries, but in much of
the developing world, where life expectancy at birth has almost doubled,
and a smaller proportion live in abject poverty.
The second half of the twentieth century was beset by a menace far
worse than any that had previously imperilled our species: the threat of all-
out nuclear war. This threat has so far been averted, but it has hung over us
for more than forty years. President Kennedy himself said during the Cuban
Missile Crisis that the chance of nuclear war was "somewhere between one
out of three and even." The risk was of course cumulative for several
decades: at any time the response to a crisis could have escalated out of
control; the superpowers could have stumbled towards Armageddon
through muddle and miscalculation.
The Cuban missile standoff in 1962 was the event that brought us
closest to a premeditated nuclear exchange. According to the historian
Arthur Schlesinger Jr., one of Kennedy's aides at that time, "This was not
only the most dangerous moment of the Cold War. It was the most
dangerous moment in human history. Never before had two contending
powers possessed between them the technical capacity to blow S up the
world. Fortunately, Kennedy and Khrushchev were leaders of restraint and
sobriety; otherwise, we probably wouldn't be here today."
Robert McNamara was then the US secretary of defense, as he also
was during the escalation of the Vietnam War. He later wrote that "Even a
low probability of catastrophe is a high risk, and I don't think we should
continue to accept it. ... I believe that was the best-managed cold war crisis
of any, but we came within a hairbreadth of nuclear war without realising it.
It's no credit to us that we missed nuclear war—at least, we had to be lucky
as well as wise. ... It became very clear to me as a result of the Cuban
missile crisis that the indefinite combination of human fallibility (which we
can never get rid of) and nuclear weapons carries the very high probability
of the destruction of nations."
We were all dragooned into this gamble throughout the Cold War
era. Even the pessimists probably didn't rate the risk of nuclear war as being
as high as fifty percent. So we shouldn't be surprised that we and our
society survived; it was more likely that we would than that we wouldn't.
Nonetheless, this does not necessarily mean that we were exposed to a
prudent risk; nor does it vindicate the policy of the superpowers for several
decades: nuclear deterrence by threat of massive retaliation.
Was the Risk Worth It?
Suppose you are invited to play Russian roulette (with one bullet in a
pistol with six chambers) and told that if you survive, you will win fifty
dollars. The most likely outcome (five to one in your favour) is that you
will indeed end up better off: still alive, and with an extra fifty dollars in
your pocket. Nonetheless, unless you hold your life very cheap indeed, this
would be an imprudent—indeed blazingly foolish—gamble to have taken.
The payoff would have to be very large before a sensible Person would risk
his or her life at these odds: many might be tempted if the potential prize
were five million dollars rather than just fifty. Likewise, if you had a
medical condition with a very poor prognosis without an operation, then—
but only then—you might opt for surgery that carried a one in six chance of
fatality.
28
So was it worth subjecting ourselves to the risks to which the entire planet
was exposed during the Cold War? The answer depends, obviously, on what the
probability of nuclear war actually was, something on which we can do no better
than accept the views of officials like McNamara, who seems to rate it as having
been substantially higher than one in six. But the answer also depends on our
assessment of what would have happened without nuclear deterrence: how likely
Soviet expansion would have been, and whether, in the words of the old slogan,
you would "rather be red than dead." It would be interesting to , know what risk
the other leaders during that period actually believed they were exposing us to, and
what risks most citizens would have accepted if they had been in a position to give
informed consent. I personally would not have chosen to risk a one in six chance of
a disaster that would have killed hundreds of millions and shattered the physical
fabric of all our cities, even if the alternative was a certainty of a Soviet takeover of
Western Europe. And of course the devastating consequences of nuclear war would
have spread far beyond the countries that perceived that they were defending
themselves against a genuine threat, and whose governments had implicitly taken
this gamble: most of the Third World, already vulnerable to natural disasters, had
this still greater hazard imposed on them.
A Science-Fuelled Arms Race
The Bulletin of Atomic Scientists was founded at the end of World War II by
a group of physicists, based in Chicago, many of whom had worked at Los Alamos
on the Manhattan Project, designing and building the atomic bombs dropped on
Hiroshima and Nagasaki. It is still a thriving and influential journal, with a focus on
arms control and nuclear policy. 29
The "logo" on the cover of each issue is a clock, the closeness of whose
hands to midnight indicates how precarious the world situation is—or is thought to
be by the Bulletin's editorial board. Every few years (sometimes more often) the
minute hand is shifted, either forwards or backwards. These clock adjustments,
stretching from 1947 to the present day, have tracked the successive crises in
international relations: it is now closer to "midnight" than it was throughout the
1970s.
The era when the clock indicated maximal hazard was actually the 1950s:
throughout that period it displayed a time of two or three minutes to midnight. In
retrospect, this seems a correct judgement. Both the US and the Soviet Union ac-
quired H-bombs during that decade, as well as larger numbers of atomic (fission)
weapons. In retrospect, Europe was lucky to have escaped nuclear devastation in
the 1950s. So-called battlefield nukes (one called the "Davy Crockett") were held at
the battalion level; safeguards were less sophisticated than they later became, and
there was real danger of a nuclear war starting by misjudgement or inadvertence;
once triggered, it could have escalated out of control. The world seemed on a still
shorter fuse when bombers were supplemented by much faster ballistic missiles that
could cross the Atlantic within half an hour, allowing the other side only a few
minutes to make the fateful choice whether to retaliate massively before their own
arsenal was destroyed.
After the Cuban Missile Crisis, the nuclear danger rose higher on the
political agenda: there was greater impetus towards arms control treaties,
starting with a ban on nuclear tests in the atmosphere, signed in 1963. But
there was no letup in the race to devise more "advanced" weaponry.
McNamara noted that "virtually every technical innovation in the arms race
has come from the US. But it has always been quickly matched by the other
side." This syndrome was exemplified by
30
the main development in the late 1960s. Engineers then devised how to carry
multiple warheads on a single missile, and to aim them independently at different
targets. This so-called MIRVing (the acronym stands for "multiple independently
targeted reentry vehicle") was dreamed up by US technologists and then
implemented both by them and by their Soviet counterparts. The net result of this,
and other innovations, was to make both sides less secure. Each put the "worst
case" construction on whatever the other side did, overestimated the threat, and
overreacted.
Another innovation—antimissile missiles to protect cities and strategic sites
against incoming warheads—was reined in by a bargain between the superpowers,
the Antiballistic Missile (ABM) Treaty. Scientists helped to broker this agreement
by behind-the-scenes arguments that any defence would destabilise the "balance of
terror" and lead to countermeasures that would negate it.
In early 1980s the Bulletin's clock was near midnight again. At that time,
new medium-range nuclear weapons were introduced into the UK and Germany,
allegedly to make more credible the threat of Western retaliation to a Soviet attack
on Western Europe. The main issues were still how to reduce the ever-present risk
of escalation towards catastrophic nuclear war, whether by malfunction,
miscalculation, or premeditated strategy. The risk in a single year may have been
small, but the probabilities would have multiplied if conditions had not changed.
The nuclear stockpile in the 1980s was equivalent to ten tons of TNT for
each person in Russia, Europe, and America. Carl Sagan and others initiated a
debate about whether an all-out nuclear exchange would trigger a nuclear winter: a
worldwide blocking-out of the Sun, with results, including mass extinction, similar
to those that would be triggered by the impact of a
31
giant asteroid or comet. The eventual best guess was that not even the
detonation of ten thousand megatons would have caused a prolonged worldwide
blackout, though there are still uncertainties in the modelling (in particular, how
high in the stratosphere the debris would reach, and how long it would stay there).
But the "nuclear winter" scenario raised the disquieting prospect that the main
victims of a nuclear war would be the populations of South Asia, Africa, and Latin
America, mostly noncombatants in the Cold War.
This was the time of the Strategic Defence Initiative—"Star Wars"-
—which led to rearguing of the case for the Anti Ballistic Missile Treaty. It
seemed technically impossible to construct a defensive "shield" effective
enough to achieve President Reagan's proclaimed goal of making nuclear
weapons "impotent and obsolete"; countermeasures always gave advantage
to the offence. This treaty is now again under threat from the United States
because it impedes the development of an antimissile defence system
against putative missile launches from "rogue states." The main objection to
this type of defensive system is that even if after vast expense and effort it
worked, it would fail to counter the most basic nuclear threat from the
"rogue states," the low-tech delivery of a bomb by ship or truck. Abrogation
of the ABM treaty would also be regrettable because it would open the way
to the "weaponisation" of space. Anti-satellite weapons are entirely feasible
and would be relatively easy to develop. Compared to the challenge of
intercepting an incoming missile, an object in a long-lived and predictable
orbit would be a "sitting duck": communication, navigation, and
surveillance satellites could easily be knocked out. Another risk is that a
"rogue state" might be tempted to neutralise satellite-based antimissile
defences by polluting space with orbiting debris, a stratagem that would
stymie any use of space by low-orbiting satellites.
32
Solly Zuckerman, a long-time science adviser to the UK government, was
(after his retirement) as eloquent as Robert Mc-Namara in denouncing the
dangerous absurdity of the chain of events that had built up the US and Soviet
nuclear stockpiles to such a grotesque "overkill" level. According to Zuckerman,
"The basic reason for the irrationality of the whole process [was] the fact that ideas
for a new weapon system derived in the first place, not from the military, but from
different groups of scientists and technologists. ... A new future with its anxieties
was shaped by technologists, not because they were concerned with any visionary
picture of how the world should evolve, but because they were merely doing what
they saw to be their job. ... At base, the momentum of the arms race is undoubtedly
fuelled by the technicians in governmental laboratories and in the industries which
produce the armaments."
Workers in weapons laboratories whose skills rose above routine
competence, or who displayed any originality, added their iota to this menacing
trend. In Zuckerman's view the weapons scientists "have become the alchemists of
our times, working in secret ways that cannot be divulged, casting spells which
embrace us all. They may never have been in battle, they may never have
experienced the devastation of war; but they know how to devise the means of
destruction."
Zuckerman was writing in the 1980s. Further innovations would by now
have ratcheted up the nuclear arms race by several more notches had not the agenda
changed utterly. After the end of the Cold War the threat of a massive nuclear ex-
change no longer loomed so imminently over us (though thousands of missiles are
still deployed by the US and Russia). In the early 1990s the Bulletin's clock was put
back to seventeen minutes to midnight. But it has been creeping forward again
since then: in 2002 it was at seven minutes to midnight. We are confronted by
proliferation of nuclear weapons (in India and Pakistan, for instance), and by
bewildering new risks and uncertainties. These may not threaten a sudden
worldwide catastrophe—the Doomsday clock is not such a good metaphor— but
they are, in aggregate, as worrying and challenging. There seems something almost
comfortable, at least in retrospect, about the paralytic but relatively predictable
politics of Leonid Brezhnev's "era of stagnation" and the superpower rivalry.
Huge nuclear stockpiles persisted throughout the 1990s, as indeed they still
do. Arms-control agreements to cut the number of deployed nuclear weapons are
welcome, but they pose the problem of managing and disposing of the twenty or
thirty thousand bombs and missiles still lying around. Treaties require that most of
these warheads be dismantled. As an immediate measure, they can be put in a state
of lower readiness or alertness; targeting programmes can be countermanded; war-
heads can be taken out of missiles and stored separately. This obviously puts
everything on a longer fuse, and into a mode where less manpower and expertise is
needed to maintain the arsenal safely. But it will take much longer—and be a major
technical challenge in itself—finally to get rid of all these weapons, and to dispose
safely of their uranium and plutonium. Highly enriched uranium 235 can be
rendered less dangerous, though still usable in peaceful nuclear reactors, by mixing
it with uranium 238. In 1993 the US agreed to buy from Russia, over a twenty-year
period, up to five hundred tonnes of formerly weapons-grade uranium in this
diluted form. Disposing of plutonium is less straightforward. The Russians are
reluctant to regard this hard-won material as "waste": however, existing nuclear
power stations do not use the kind of "breeder" reactors that can directly burn
plutonium. The best options are to bury it, or to render it unusable in weapons by
mixing it with radioactive waste or partially burning it in a nuclear reactor.
According to Richard Garwin and Georges Charpak, "The
33
34
total of excess material in Russia would provide something like 10,000
plutonium weapons and 60,000 uranium implosion weapons. Securing this material
is truly a daunting task."
Until this disposal has been achieved, security and a reliable inventory must
be maintained for all the weapons in the former Soviet Union: otherwise, far more
could go astray than the entire stock of the "minor" nuclear powers. Indeed there is
real disquiet—though no firm evidence—that during the transitional turbulence in
the early 1990s, terrorist or rebel groups may already have purloined such weapons.
Construction of a long-range missile carrying a compact warhead is still far
beyond the resources of dissident groups. But even this prospect has become less
daunting and cannot be dismissed. For instance, now that the signals from GPS
satellites are available to everyone, a cruise-type missile could be guided by a
commercially available package. And a ground-hugging missile would be harder to
track and intercept than a ballistic missile. Far less technically demanding
techniques, which also would evade antimissile defences, include the detonation of
a weapon transported in a truck or ship and the construction of a crude explosive
device assembled, using stolen enriched uranium, in a city apartment. Unlike a
missile-launched bomb, this would leave no trace of its provenance.
Countering the Spread of Weapons
In one respect, at least, the nuclear scene could be a lot worse. The number
of nuclear powers has increased, but not as fast as many pundits had predicted.
There may be up to ten, if one counts undeclared proliferators such as Israel; but at
least twenty countries could have surmounted the technical threshold had they
wished to but instead have eschewed any nuclear
35
role: Japan, Germany, and Brazil, for instance. South Africa developed six
nuclear weapons but has now dismantled them
When it began in 1967, the Nonproliferation Treaty (NPT) took cognisance
of the special status of the five powers that already then possessed nuclear
weapons: the US, the UK, France, Russia, and China. To make this
"discrimination" less unpalatable to other nations, the treaty stated that these nu-
clear powers should "pursue negotiations in good faith on effective measures
relating to cessation of the arms race . . . and the discontinuance of all test
explosions of nuclear weapons for all time."
The NPT would have a fairer wind behind it if these five nations, as
their side of the bargain, cut back their own arsenals more drastically.
According to current treaties, it will take ten years before the US
deployment falls even to two thousand warheads; moreover, the
decommissioned warheads will not be irreversibly destroyed, but merely
held in storage. The nuclear powers have also dragged their feet on a
comprehensive test ban, which would curb the development of still more
sophisticated weapons. The US has refused to ratify this treaty. Occasional
testing is claimed to be needed to check that existing weapons in the
stockpile remain "reliable"—in other words, that they would go off when
they were supposed to. Debate continues about the extent to which
reliability could be adequately assured by testing the components
separately, by computer simulations, for example. It is in any case unclear
how important this assurance is except for an aggressor planning a first
strike: a nuclear missile remains a deterrent even if there is only a fifty
percent chance its payload will explode. It is also claimed that tests are
needed to ensure that the weapons are "safe"— that they will not explode or
release dangerous radioactivity if accidentally mishandled. Another
argument against a comprehensive test ban is that compliance cannot be
adequately veri-
36
fied. Although underground tests of above a few kilotons have an
unambiguous seismic signature, those below a kiloton may be drowned by the large
number of small earthquakes, and can be muffled if they are carried out in large
cavities. There is debate about how many seismic stations are needed for verifica-
tion; and about how seismic evidence could be supplemented by intelligence, or by
satellite surveillance. A report from the US National Academy of Sciences argues
that undetectable tests would not be feasible, and tests are unnecessary to maintain
existing stockpiles, only to develop new "advanced" weapons.
A comprehensive test ban would not in itself stop proliferation, because it is
possible to make a credible first-generation fission bomb without a test. But a ban
would inhibit the existing nuclear powers (particularly the US) from developing
new types of bomb, and thereby improve the climate for the Non-proliferation
Treaty, which enjoins all nuclear powers to reduce their arsenals. To counter
proliferation, it is far more crucial to extend the role of the International Atomic
Energy Agency in keeping track of fresh nuclear material and carrying out on-site
inspections. This, of course, was the issue that triggered the crisis over Iraq.
But the most important determinant will be whether nations perceive an
incentive to join the nuclear club. The existing nuclear powers could help by
downplaying the role of nuclear arms in their defence postures. Recent statements
by the US, and even the UK, on the possible use of low-yield nuclear weapons to
attack underground hideouts are in this regard a real step backwards. Such
declarations blur the nuclear threshold, and make the use of nuclear weapons less
unthinkable; they increase the incentive for other countries to get their own bombs,
an incentive that is already strengthening because there seems no other way to deter
or counter unwelcome pressure
37
from the US, whose advantage in "smart" conventional weaponry is so
overwhelming that the superpower can impose its will on other nations with
minimal human cost to itself.
Concerned Scientists
The Chicago atomic scientists were not the only ones who attempted from
outside government to influence the political debate about the post-World War II
nuclear threat. Another group founded a series of conferences that took the name of
the village Pugwash, in Nova Scotia, where the first such conference was held
under the sponsorship of a Canadian millionaire, Cyrus Eaton, who had been born
there. The participants in early Pugwash conferences came from the Soviet Union
as well as the West, and had generally been active in World War II; they had
worked on the bomb project, or on radar, and had maintained an informed concern
ever since. Particularly during the 1960s and 1970s, the Pugwash conferences
provided valuable informal contact between the US and the Soviet Union when
there were few formal channels.
There are still some remarkable survivors from this generation. The
most senior is Hans Bethe, born in 1906 in Strasbourg, in Alsace-Lorraine.
In the 1930s he was already eminent as a nuclear physicist. He moved from
Germany to an academic post in the US and during World War II became
head of the theoretical division at Los Alamos. He afterwards returned to
Cornell University, where even in the new century he has continued to be
active in promoting arms control, as well as pursuing research (his main
recent interest being in the theory of exploding stars and supernovae). Bethe
must rank as the most universally respected of all living physicists,
acclaimed
38
39
not only for his science but for his sustained concern and involvement with
its implications. He is perhaps unique among physicists in having published fine
work for more than seventy-five years. In 1999 his attitude towards military
research hardened, and he urged scientists to "cease and desist from work creating,
developing, improving, and manufacturing nuclear weapons and other weapons of
potential mass destruction" on the grounds that this fuelled the arms race.
Another Los Alamos veteran whom I have been privileged to know is Joseph
Rotblat. Two years younger than Bethe, he experienced in his Polish childhood the
hardships of World War I, and began his career as a research scientist in his home
country. In 1939 he came as a refugee to England to work with the eminent nuclear
physicist James Chadwick at Liverpool; his wife was never able to join him, and
she perished in a concentration camp. Rotblat joined the Manhattan project at Los
Alamos as part of the small British contingent. But he chose to leave prematurely
when it became clear that German defeat was near, because in his mind the bomb
project could be justified only as a counterbalance to a possible nuclear weapon in
Hitler's hands. Indeed, he recalls having been disillusioned by hearing General
Groves, head of the project, saying as early as March 1944 that the main purpose of
the bomb was "to subdue the Russians."
Rotblat returned to England, where he became a professor of medical
physics, doing pioneering research into the effects of exposure to radiation. In 1955
he encouraged Bertrand Russell to prepare a manifesto stressing the urgency of
reducing the nuclear peril. One of Einstein's last acts was to agree to be a
cosignatory. This eloquent manifesto, whose authors claimed to be "speaking on
this occasion not as members of this or that nation, continent or creed, but as human
beings, members of the species Man, whose continued existence is in doubt," led to
the initiation of the Pugwash conferences in 1957; ever since, Rotblat has
been their "prime mover" and untiring inspiration. When the achievements of these
conferences were recognised by the 1995 Nobel Peace Prize, it was fitting that half
the award went to the Pugwash organisation and half to Rotblat personally. Rotblat,
now aged 94, still pursues, with the dynamism of a man half his age, his unflagging
campaign to rid the world completely of nuclear weapons. This is often derided as
an unrealistic goal, espoused only by fringe groups and idealists of a woolly and
unthinking kind. Rotblat remains an idealist, but without illusions about the gap
between hope and expectation, and his cause is broadening its support.
"The proposition that nuclear weapons can be retained in perpetuity and
never used—accidentally or by decision—defies credibility." This firm declaration
comes from a 1997 report of an international group convened by the Australian
government and known as the Canberra Commission. Its members included not
only Rotblat but also Michel Rocard, former prime minister of France; Robert
McNamara; and retired military and air force generals. The commission noted that
the only military utility of nuclear weapons was to deter their use by others, and put
forward step-by-step proposals for moving, in a politically stable way, towards a
world without nuclear weapons.
Those who were uprooted from placid academic laboratories to join the
Manhattan project belonged to what seems in retrospect the "golden generation" of
physicists: many had been pivotal in establishing our modern view of atoms and
nuclei. They were mindful that fate had plunged them into epochal events. Most of
them returned to academic work in universities, but sustained a lifelong concern
with nuclear weapons. All were deeply marked by their involvement, but in
divergent ways, as exemplified by the contrasting postwar careers of the
40
two most prominent personalities, J. Robert Oppenheimer and Edward
Teller. (Andrei Sakharov, the most celebrated Soviet counterpart of these two
Americans, came from a slightly younger generation, having been involved in the
postwar development of the H-bomb.)
The Chicago atomic scientists, and the pioneers of the Pug-wash movement,
set an admirable example for researchers in any branch of science that has grave
societal impact. They did not say that they were "just scientists" and that the use
made of their work was up to politicians. They took the line that scientists have a
duty to alert the public to the implications of their work, and should retain a
concern with how their ideas are applied. We feel there is something lacking in
parents who are unconcerned about what happens to their children in adulthood,
even though it is generally beyond their control. Likewise, scientists should not be
indifferent to the fruits of their research: they should welcome (and indeed try to
foster) benign spin-offs, but resist, so far as they can, dangerous or threatening
applications.
In the present century the dilemmas and threats will come from biology and
computer science, as well as from physics: in all these fields society will insistently
need latter-day counterparts of Bethe and Rotblat. University scientists and
independent entrepreneurs have a special obligation because they have more
freedom than those in government service and company employees subject to
commercial pressures.
4. POST-2000 THREATS Terror and Error
Within twenty years, bioterror or bioerror could kill a million people.
What does this presage for later decades?
I AM FINALISING THIS CHAPTER IN DECEMBER 2002, just over a
year after the September 11 attacks on the United States. There is continuing fear
that further outrages will inscribe other tragic dates in our collective memories. A
succession of suicide bombers is terrorising Israel. The bombers are intelligent
young Palestinians (women as well as men) with warped idealism. In the late
twentieth century, organised terrorists groups with rational political aims (for
instance, those operating in Ireland) refrained from the very worst they could have
done because, even with their distorted perspective, they reckoned that beyond a
certain threshold an outrage would be
41
42
counterproductive to their cause. The Al Qaeda terrorists who crashed the
planes on the World Trade Center and the Pentagon had no such inhibitions. If such
groups were to obtain a nuclear weapon, they would willingly detonate it in a city
centre, killing tens of thousands along with themselves; and millions around the
world would acclaim them as heroes. The consequences could be even more
catastrophic if a suicidal zealot were to become intentionally infected with
smallpox and trigger an epidemic; in future there could be viruses even more lethal
(and without an antidote).
The Einstein-Russell manifesto had this to say about the concerns of well-
informed scientists in the 1950s with regard to the nuclear threat: "None of them
will say that the worst results are certain. What they do say is that these results are
possible, and no one can be sure that they will not be realised. We have not yet
found that the views of experts on these questions depend in any degree on their
politics or prejudices. They depend only, so far as our researches have revealed, on
the extent of the particular expert's knowledge. We have found that the [experts]
who know most are the most gloomy."
The same could be said today about other risks that now loom just as large.
Twenty-first-century technology confronts us with a diverse array of lethal
prospects that were not yet on the horizon during the Cold War era. Moreover, the
potential perpetrators are also more diverse, and more elusive. The prime new
threats are "asymmetric": they come not from nation states but from subnational
groups, and even from individuals.
Even if all nations impose strict regulations on the handling of nuclear
material and dangerous viruses, the chances of effective enforcement, worldwide,
are no better than current enforcement of laws against illegal drugs. Just one
infringement could trigger widespread disaster. Such risks plainly can never be
completely eliminated. But far worse, they seem set to be-
43
come more intractable and threatening. There will always be disaffected
loners in every country, and the "leverage" that each can exert is increasing. And
there are other quite different threats. In cyberspace, for instance, there is a race
between attempts to render systems more robust and secure, and the growing
ingenuity of criminals who may try to infiltrate and sabotage those systems.
Nuclear Megaterror
Nuclear "megaterrorism" is a prime risk. Tom Clancy's novel The Sum of
Our Fears, turned into a film released in 2002, portrayed devastation of a crowded
football stadium by a purloined nuclear device. Nuclear energy is a million times
more efficient, per kilogram, than chemical explosions. The bomb used in the
Oklahoma City attack, which killed over 160 people—until September 11, 2001,
the worst-ever attack on the US homeland—was equivalent to about three tonnes of
TNT. The nuclear stockpiles of the former Soviet Union and the US amount to that
much explosive power for each person in the world, and hence the danger if even a
minuscule fraction of this arsenal—even a single one of the tens of thousands of
warheads that now exist—were to go astray.
Nuclear bombs fuelled by plutonium have to be triggered by a precisely
configured implosion. This is technically challenging, perhaps too challenging for
terrorist groups. But plutonium could be coated on the surface of a conventional
bomb to make a "dirty bomb." Such a weapon would cause no more immediate
fatalities than a large conventional bomb, but would create extensive long-term
disruption because it would pollute a large area with unacceptable levels of
radiation. A still greater terrorist risk comes from enriched uranium (separated U-
235)
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45
because it is far easier to make a genuine nuclear explosion using this fuel.
The Nobel physicist Luis Alvarez claimed, "With modern weapons-grade uranium.
. . terrorists would have a good chance of setting off a high-yield explosion simply
by dropping one half of the material onto the other half. Most people seem unaware
that if separated U-235 is to hand, it's a trivial job to set off a nuclear explosion,
whereas if only pluto-nium is available, making it explode is the most difficult
technical job I know." Alvarez is unduly downplaying the difficulty of making a
uranium weapon. However, an explosion could be achieved by using a cannon or
mortar to propel a subcritical mass, configured as a shell or bullet, into another
subcritical mass shaped into a ring or hollow cylinder.
A nuclear explosion at the World Trade Center, involving two grapefruit-
sized lumps of enriched uranium, would have devastated three square miles of
southern Manhattan, including the whole of Wall Street. It would have killed
hundreds of thousands if it went off during working hours. Similar devastation
would arise if there were attacks on other cities. And conventional explosives could
trigger disaster on almost the same scale if, for example, they were set off so as to
detonate huge storage tanks of oil or natural gas. (Indeed, the 1993 bombing of the
World Trade Center could have been as destructive as that of 2001 if the explosion,
set off at one corner of the foundations, had caused one tower to topple and crash
onto the other tower.)
"We have slain the dragon, but are now living in a jungle full of poisonous
snakes," said James Wolsey, former director of the CIA, in 1990. He was referring
to the turbulence that followed the collapse of the Soviet Union and the end of the
Cold War. A decade later, his metaphor is even more appropriate for the elusive
groups that threaten us.
These short-term risks highlight the urgency of safeguarding
the plutonium and enriched uranium in the republics of the former Soviet
Union. It could be already too late. Stewardship was lax in the political turmoil of
the early 1990s: Chechen rebels and other subnational groups may already have
appropriated some weapons.
In 2001 the US cut back on a proposed three-billion-dollar subvention to
Russia and the other states of the former Soviet Union for decommissioning
weapons, preventing "defection" of scientific experts, and disposing of
plutonium—efforts that surely deserve far more urgent priority than "national
missile defence." A positive development, however, has been the Nuclear Threat
Initiative, chaired by ex-Senator Sam Nunn and funded primarily by Ted Turner,
founder of CNN, which is using its own resources and political leverage to energise
threat-reduction measures.
Terrorism is a new risk affecting our attitude to civilian nuclear power
stations—augmenting the traditional liabilities of high capital cost,
decommissioning problems, and the legacy of toxic waste left for future
generations. A power station harbours not only the highly radioactive "core," but
also a stock of spent fuel-rods that could be more vulnerable. Even the latter, if set
on fire, could release ten times more cesium-137 (with a thirty-year half-life) than
the Chernobyl accident.
Designers of nuclear reactors aimed to reduce the probability of the worst
accidents to less than one per million "reactor years." To do such calculations, all
possible combinations of mishaps and subsystem failures have to be included.
Among these is the possibility that a large aircraft might crash onto the containment
vessel. Air accident records (and projections into the future) tell us how many
aircraft are likely to fall out of the sky. In the whole of Europe and North America
it is only a few per year. The chance that one of them would hit a particular46
Our Final Hour
building is reassuringly low, much less than one in a million per year. But we
now know that this is not the right calculation. It overlooks the possibility, now
nightmarishly familiar, that kamikaze-style terrorists could aim for just such a
target, using a large fully fuelled jet, or a smaller plane loaded with explosives. The
chance of such an event cannot be assessed even by the most astute technicians or
engineers: it is a matter of political or sociological judgement. But one would surely
have to be a naive optimist to rate it as less than one in a hundred per year. If this
high estimate had been fed into risk assessments when nuclear power stations were
being planned, then current designs might not have been sanctioned. It could
become incumbent on all new designs to meet safety standards that may even
require them to be put underground.
The role of nuclear power could in any case decline during the next twenty
years if existing nuclear power stations reach the end of their lives and are not
replaced. Many thousands of new power stations would be needed if nuclear energy
were to contribute substantially to the worldwide goal of reducing greenhouse
emissions. Quite apart from the sabotage and terrorism threats, the risk of accidents
rises if maintenance is lax. The poor safety records of some Third-World airlines
endanger primarily those who fly in them; poorly maintained reactors pose a threat
that doesn't respect national boundaries.
Nuclear power could have a brighter future if novel kinds of fission reactors
that overcome the safety and decommissioning problems of present designs came
into routine use. Another long-range prospect is nuclear fusion: a controlled version
of the process that keeps the Sun shining and powers the H-bomb. Fusion has long
been touted as an inexhaustible source of energy. But the goal has receded: after a
false dawn back in the 1950s before the real difficulties were realised, fusion has
consistently seemed at least thirty years away.
47
The prime advantage of nuclear power, whether fusion or fission, is that it
simultaneously solves two problems: limited oil reserves and global warming. But a
preferable option, on both environmental and security grounds, would be renewable
sources. These will surely supply an increasing fraction of the world's needs, but
won't be able to supply total demand without some technical breakthroughs. Wind
turbines alone won't be enough, and current solar energy conversion is too expen-
sive and inefficient. But if sunlight could be harnessed by some cheap and effective
photovoltaic material that can be draped over huge areas of unproductive land, then
the so called "hydrogen economy" would be feasible: solar-generated electric
power would extract hydrogen from water; this hydrogen can then be used in fuel
cells, which substitute for internal combustion engines.
Biothreats
More disquieting than nuclear dangers are the potential hazards stemming
from microbiology and genetics. For decades several nations have had substantial
and largely secret programmes to develop chemical and biological weapons. There
is ever-growing expertise in designing and dispersing lethal pathogens, not least in
the US and UK, where there are continuing research programmes to improve
countermeasures against biological attacks. Iraq is suspected of pursuing an of-
fensive programme; several other countries (South Africa, for instance) have had
such programmes in the past.
Back in the 1970s and 1980s the Soviet Union was engaged in the largest-
ever mobilisation of scientific expertise to develop biological and chemical
weapons. Kanatjan Alibekov was at one time the number-two scientist in the Soviet
Biopreparat
48
programme; he defected to the US in 1992, Westernising his name to Ken
Alibek. According to his book Biohazard, he was in charge of more than thirty
thousand workers. He recounts the efforts made to modify organisms to make them
more virulent and more resistant to vaccines. In 1992, Boris Yeltsin admitted
something that Western observers had long suspected: at least 66 mysterious deaths
in the city of Sverdlovsk that occurred in 1979 were caused by anthrax spores that
had leaked from a Biopreparat laboratory.
The problem of detecting illicit fabrication of nuclear weapons is as nothing
compared with the task of verifying national compliance with treaties on chemical
and biological weapons. And even that is easy compared with the challenge of
monitoring subnational groups and individuals. Biological and chemical warfare
were long regarded as cheap options for states without nuclear weapons. But it no
longer requires a state, or even a large organisation, to mount a catastrophic attack:
the resources needed could be acquired by private individuals. The manufacture of
lethal chemicals or toxins requires modest-scale equipment that is, moreover,
essentially the same as is needed for medical or agricultural programmes: the
techniques and expertise are "dual use." This is another contrast with nuclear
programmes, where the uranium enrichment needed for efficient fission weapons
requires elaborate equipment with no legitimate alternative use. In the words of
Fred Ikle, "The knowledge and techniques for making biological superweapons will
become dispersed among hospital laboratories, agricultural research institutes, and
peaceful factories everywhere. Only an oppressive police state could assure total
government control over such novel tools for mass destruction."
Thousands of individuals, perhaps even millions, may someday acquire the
capability to disseminate "weapons" that could cause widespread (even worldwide)
epidemics. A few adherents
49
of a death-seeking cult, or even a single embittered individual, could unleash
an attack. Indeed, there have already been small-scale bioattacks, but fortunately,
the techniques were too primitive, and too ineptly executed, to accomplish even as
much as a conventional explosive could have done. In 1984 some followers of the
Rajneeshee cult (he of the yellow robes and fifty Rolls Royces) contaminated some
salad bars in Wasco County, Oregon, with salmonella, and 750 people were
stricken with gastroenteritis. The motive for the attack was apparently to in-
capacitate votes in a local election, and thereby influence the outcome of a planning
application for the cult's commune. But the origin of this epidemic was inferred
only a year later, highlighting the problem of tracing the perpetrators of any
biological attack. In the early 1990s the Aum Shinrikyo sect in Japan developed
various agents including botulinum toxin, Q fever, and anthrax. They released the
nerve gas sarin in the Tokyo subway, killing twelve; the attack could have been far
more devastating had they been more successful in dispersing the gas in the air.
In September 2001, envelopes containing anthrax spores were sent to two US
senators and to several media organisations. Five people died—a tragedy, but on a
scale no larger than everyday road crashes. However—and this is an important
portent—the blanket media coverage in the US led to a "dread factor" that pervaded
the entire nation. One can readily envisage the massive consequence for the
national psyche of an outrage that killed thousands. The actual impact of a future
attack could be greater if an antibiotic-resistant variant of the bacterium were used,
and, of course, if it were dispersed effectively. This threat is leading to a biological
"arms race": efforts to develop drugs and viruses that can target specific bacteria,
and also sensors to detect pathogens in very low concentrations.
50
What Could a Bioattack Currently Achieve?
Many studies and exercises have been undertaken in order to gauge the
possible impact of a bioattack and how emergency services might respond to it.
Back in 1970 the World Health Organisation estimated that a release of fifty
kilograms of anthrax spores from an aeroplane flying upwind of a city could cause
nearly one hundred thousand deaths. More recently, in 1999, several scenarios were
explored by the Jason group, a consortium of highly rated academic scientists who
do regular consulting for the US Department of Defense. The group considered
what would happen if anthrax were released in the New York subway. Spores
would be dispersed along the tunnel system and by passengers. If the release had
been covert, the first evidence would emerge a few days later when the victims (by
then widely spread over the country) visited their doctors with symptoms.
The Jason group also studied the effects of a chemical agent, ricin, which
attacks ribosomes and interferes with the chemistry of proteins. A lethal dose is
only ten micrograms. However, the fact that the sarin attack on the Tokyo subway
did not kill thousands showed that the spread of the agent is not a trivial technical
challenge. Details have been released of experiments on (nontoxic) aerosol
dispersals carried out in the 1950s and 1960s in the US and the UK. These were
done in the London underground, the New York subway, and in San Francisco.
Achieving efficient dispersal in the air is a generic problem with all chemical
agents, as it is with biological agents (like anthrax) that are not infectious. To say
that a few grams of an agent could in principle kill millions may be true, but it may
also be misleading (just as it would be misleading to say that one man could father
a hundred million children; spermatozoa are plentiful enough, but dispersal and
delivery would be a real challenge).
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For infectious diseases, initial dispersal is less crucial than for anthrax
(which cannot be passed on from person to person); even a localised release,
especially in a mobile population, could trigger a widespread epidemic. Perhaps the
most fearful prospect, among known viruses, is smallpox. Through a magnificent
worldwide effort in the 1970s, spearheaded by the World Health Organisation, the
disease has been completely eradicated. Rather than making the virus extinct,
stocks have been maintained in two locations, the Center for Disease Control, in
Atlanta, USA, and the ominously named Vector Laboratory in Moscow. The
justification for preserving these viruses is that they could be used to help develop
vaccines. However, there is growing concern that clandestine caches of the virus
may exist in other countries, raising fears of smallpox bioterror.
Smallpox is highly contagious (almost as infectious as measles) and kills
about one-third of those who succumb to it. There are several published studies of
what would happen if this deadly virus were released. Even if the epidemic were
contained, and casualties ran only into hundreds, the effect on a large city could be
devastating. There would be a run on medical supplies, especially if vaccines were
scarce. But an actual death toll could run into millions, especially if the epidemic
spread internationally.
In July 2001 an exercise, entitled "Dark Winter," simulated a covert
smallpox attack on the United States and the response and countermeasures to it. In
this exercise, roles were played by experienced figures: the former US senator Sam
Nunn played the president, and the governor of Oklahoma played himself. It was
assumed that aerosol clouds contaminated with smallpox virus were released
simultaneously in three locations—shopping malls—in different states. The
scenario led, in the worst case, to three million people being infected (of whom a
third would have died). Prompt vaccination would eventually
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53
have choked off the spread of the disease (the vaccine is still effective even
four days after infection occurs). But an infection that spread worldwide, as it
would if the initial release were at an airport or in an airliner, could start a runaway
epidemic in countries where vaccine was not so readily available as in the US—
worst of all, perhaps, in the congested megacities of the developing world. The
incubation period is twelve days, so by the time the first case was manifest, those
originally infected would have spread around the world, and induced secondary
infections. It would be too late to impose any effective quarantine.
"Smallpox 2002: Silent weapon," a docudrama broadcast by the BBC,
portrayed a single suicidal fanatic in New York who infected enough people to
trigger a pandemic that claimed sixty million victims. This scarifying scenario was
based on a (perhaps questionable) computer model of how the virus would spread.
When mathematicians try to compute how an epidemic develops, the most crucial
factor that enters their calculations is the number of people a typical victim infects,
known as the "multiplier." For this particular model, this number was assumed to
be 10. But some experts have argued that smallpox is not so infectious, that it
typically takes several hours of proximity to pass on and that these scenarios
therefore exaggerate the ease with which an infected person transmits the disease.
However, there is evidence (for instance, from a 1970 outbreak in a German
hospital) that the virus can be spread by air currents as well as physical contact.
Some experts have suggested that a multiplier of 10 may be appropriate in
hospitals, but only 5 in the community: others suggest that the multiplier could
actually be as low as 2.
Uncertainties like this are crucial in determining how readily an epidemic
could be contained by mass vaccination or quarantine. But of course, it would be
harder to control an outbreak if (as envisaged in the BBC scenario) it had spread,
before being detected, into developing countries where reaction to such an
emergency would be slower and less effective. And there will surely be other
viruses that are still more readily transmitted. In the UK an epidemic of foot and
mouth disease in 2001 had disastrous countrywide consequences for agriculture
despite maximal efforts to control it. The outcome would be far worse if such an
infection were maliciously spread. Bioattacks threaten people and animals; but they
could threaten crops and ecosystems as well. Another of the Jason group's near-
term scenarios was an attempt to sabotage agricultural production in the American
Midwest by introducing the fungus known as "wheat rust," a naturally occurring
fungus that sometimes destroys up to ten percent of the crop in California.
One feature common to all biological attacks is that they cannot be detected
until it is too late, perhaps even not even before the effects have diffused
worldwide. Indeed, the use of bioweapons in organised warfare has been inhibited
not only be moral reservations, but because the time lag and spread cannot be
controlled by military commanders. But this delay is an attraction to the lone
dissident or terrorist, because the provenance of an attack—when or where the
pathogen was released—can be readily camouflaged. The prospects of early de-
tection would be improved by rapid nationwide sharing and analysis of medical
information so that it would be easier to spot a sudden rise in the number of patients
displaying a specific set of symptoms, or the near-simultaneous incidence of some
rare or anomalous syndrome.
Any attack would induce severe disruption and panic. The alarmist reporting
of the 2001 anthrax episode in the US exemplified how even a localised threat can
affect the mindset of a whole continent. By amplifying fears and fuelling hysteria,
media coverage would guarantee that even a smallpox epidemic at the less severe
end of the spectrum of predictions would disrupt ordinary life worldwide.
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All pre-2000 epidemics (with the possible exception of the 1979 Russian
anthrax release) were caused by naturally occurring pathogens. But the biothreat
has been aggravated by the advance of biotechnology. According to a report issued
in June 2002 by the US National Academy of Sciences, "Just a few individuals with
specialised skills and access to a laboratory could inexpensively and easily produce
a panoply of lethal biological weapons that might seriously threaten the US
population. Moreover, they could manufacture such biological agents with
commercially available equipment—that is, equipment that could also be used to
make chemical, pharmaceuticals, foods, or beer—and therefore remain
inconspicuous. The deciphering of the human genome sequence and the complete
elucidation of numerous pathogen genomes . . . allow science to be misused to
create new agents of mass destruction."
The report notes that the new technology should also, as an "upside," lead to
quicker ways of identifying and reacting to a pathogen release, but its overall
message is disquieting. It recognises that a skilled "loner" could perpetrate a
catastrophic epidemic, even though the focus is now on terrorist groups. All over
the world there are people with the expertise to undertake genetic manipulations
and cultivate microorganisms. George Poste, a British biotechnologist and
government advisor who now works in the US, conjectures that "It would be
interesting to reflect, if [the "Unabomber"] had been trained in the 1990s, whether
he would have chosen to use bombs or would have walked along and dropped
something into a hamburger plant as an alternative, as the ubiquity
of'Biotechnology 101' becomes increasingly commonplace in the university
curriculum around the world." (In 2002 the US approved a huge increase in funding
for biodefence. This will, as an unwelcome byproduct, disseminate such expertise
more widely.)
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Eckard Wimmer and his colleagues at the State University of New York
announced in July 2002 that they had assembled a polio virus, using DNA and a
genetic blueprint that could be downloaded from the Internet. This artificial virus
posed little hazard, because most people have been immunised against polio. But it
would be no more difficult to create variants that could be infectious and even
lethal. Experts had known for years that the kind of synthesis Wimmer did was
feasible; some criticised him for doing an unnecessary experiment just as a stunt.
But to Wimmer it was a "scary realisation" that viruses could be so readily created.
Viruses like smallpox, with larger genomes than the polio virus, pose a greater
technical challenge; moreover, the smallpox virus would not be able to reproduce
itself unless replication enzymes were added from a different pox virus. However,
some smaller and equally lethal viruses—HIV and ebola, for instance—could be
created, even now, by assembling a chromosome from individual genes, as
Wimmer did.
Within a few years, the genetic blueprints of vast numbers of viruses, as well
as of animals and plants, will be archived in laboratory databases accessible to other
scientists via the Internet. The blueprint of the ebola virus, for example, is already
archived; there are thousands of people with the skills to assemble it, using strands
of DNA that are available commercially. In the 1990s, members of the Aum
Shinrikyo cult tried to track down the naturally occurring ebola virus in Africa: it is
fortunately rare, and they failed to find it. They would now find it easier to
assemble it in a home laboratory. Home computers and the Internet have opened up
immensely greater scope for amateur scientists. In a subject like astronomy, this is
an important and unreservedly welcome development. But one would view
ambivalently the empowerment of a sophisticated community of amateur
biotechnologists.
Creation of "designer viruses" is a burgeoning technology.
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And a better understanding of the human immune system, though of crucial
medical benefit, will also make it easier for those who wish to suppress immunity.
A succession of different engineered viruses for which there was no immunity nor
antidote could have an even more catastrophic effect worldwide than AIDS is now
having in Africa (where it is reversing decades of economic advance): for instance
an equivalent of smallpox for which there is no vaccine, perhaps even a virus that
spreads even more readily than smallpox itself, or a variant of AIDS that is
transmitted like influenza, or a version of ebola with a longer gestation period.
(Outbreaks of this dreadful contagious disease are usually contained because it acts
so fast, killing its victims by eroding away their flesh before they have much
chance to infect others. In contrast, it is the slowness with which AIDS acts that
allows it to be effectively transmitted.)
Unless the capability to design new viruses is matched by corresponding
skills in designing and manufacturing vaccines targeted against them, we could find
ourselves as vulnerable as the native Americans who succumbed to diseases
brought by European settlers, to which they had no immunity.
Strains of bacteria can be developed that are immune to antibiotics. Indeed,
such bacteria are already emerging naturally as an outcome of Darwinian selection.
Some hospital wards have already been infected by "bugs" resistant even to van-
comycin, the antibiotic of last resort. Artificial engineering may "ring the changes"
more effectively than natural mutations. New organisms could be designed to attack
plants and even inorganic substances.
We may not have to wait long before new kinds of synthetic microbes are
being genetically engineered. Craig Venter, former chief executive officer of
Celera, the company that sequenced the human genome, has already announced
plans to help solve the world's energy and global warming crises by cre-
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ating new microbes: one type would dissociate water into oxygen and
hydrogen (for the "hydrogen economy"); others would feed off carbon dioxide in
the atmosphere (thereby combating the greenhouse effect) and convert it into
organic chemicals of the kind that are now made from oil and gas. Venter's tech-
nique involves making an artificial chromosome with about five hundred genes and
inserting it into an existing microbe whose own genome has been destroyed by
radiation. If this technique works, it opens up the prospects of designing new forms
of life that could feed off other materials in our environment. For example, fungi
could be designed that could feed on and destroy polyurethane plastics. Even
machines could be under threat: specially designed bacteria could change oil into a
crystalline material, and thereby clog up machinery.
Laboratory Errors
Almost as worrying are the growing risks stemming from error and the
unpredictable outcomes of experiments, rather than from malign intent. A recent
episode in Australia was a worrying portent. Ron Jackson was a researcher at the
Animal Control Cooperative Research Centre in Canberra, a government laboratory
whose main mission was to improve techniques for controlling animal pests. With
his colleague Ian Ramshaw he was researching new ways to bring down the
population of mice. Their idea was to modify the mousepox virus so that it became,
in effect, an infectious contraceptive vaccine, and use it to sterilise mice. During
these experiments, early in 2001, they inadvertently created a new, highly virulent,
strain of mousepox: their laboratory mice all died. They had added a gene for a
protein (interleukin-4) that boosted antibody production and suppressed the
immune system in the mice; in
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consequence, even animals that had previously been vaccinated against
mousepox died as well. Had these scientists been working instead on the smallpox
virus, could they have modified it to become even more virulent, so that
vaccination offered no protection against it? According to Richard Preston, "the
main thing that stands between the human species and the creation of a supervirus
is a sense of responsibility among the individual biologists."
This type of laboratory experiment, creating pathogens more dangerous than
predicted, and perhaps more virulent than have ever developed naturally, is an
exemplar of a kind of hazard that scientists will need to confront (and seek to
minimise) in other research areas. These areas include nanotechnology (and even
fundamental physics), where the consequences could be even more calamitous.
Nanotechnology holds great long-term promise, but could eventually have an even
more serious downside than any bioerror. It is conceivable—though still far from
reality—that nanomachines could be devised that can assemble copies of
themselves. If let loose, their numbers could rise exponentially, until they ran out of
"food." If their consumption were highly selective, these machines could be useful
substitutes for chemical factories, in the same way as "designer bugs" could be. But
the danger arises if nanomachines could be designed to be more omnivorous than
any bacterium, perhaps even able to consume all organic materials. Metabolising
efficiently, and utilising solar energy, they could then proliferate uncontrollably,
and not reach the Malthusian limit until they had consumed all life.
This chain of events is dubbed by Eric Drexler the "grey goo scenario." He
writes, "'Plants' with 'leaves' no more efficient than today's solar cells could out-
compete real plants, crowding the biosphere with an inedible foliage. Tough
omnivorous 'bacteria' could out-compete real bacteria. They could spread like
blowing pollen, replicate swiftly and reduce the biosphere to dust in a matter of
days. Dangerous replicators could easily be too tough, small, and rapidly spreading
to stop—at least if we make no preparations. We have trouble enough controlling
viruses and fruit flies."
The resultant population explosion in these "biovorous replicators" could
then in theory devastate a continent within a few days. This is very much a
theoretical "worst case"; nonetheless, such estimates carry the message that if the
technology of self-replicating machines were ever developed, a fast-spreading
disaster could not be ruled out.
Can the "grey goo" threat be taken seriously, even if we extend our forecast a
century ahead? A runaway plague of these replicators would not violate basic
scientific laws. But that does not make it a serious risk. To take another futuristic
technology: an antimatter-powered space rocket attaining ninety percent of the
speed of light is compatible with basic physical laws, but we know that it is
technically far beyond us. Perhaps these hyperefficient replicators, feeding off the
biosphere, are just as unrealistic as a "star ship," another example of where the "en-
velope" of what is consistent with general scientific laws (and hence theoretically
possible) is far above what is likely. Should we categorise the ideas of Drexler, and
others as scare-mongering science fiction?
Viruses and bacteria are themselves superbly engineered nanomachines, and
an omnivorous eater that could thrive anywhere would be a winner in the natural
selection stakes. So if this plague of destructive organisms is possible, Drexler's
critics might argue, why didn't it evolve by natural selection, long ago? Why didn't
the biosphere self-destruct "naturally," rather than being threatened only when
creatures designed by misapplied human intelligence are let loose? A riposte to this
argument is that human beings are able to engineer some modifications that
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nature cannot achieve: geneticists can make monkeys or corn glow in the
dark by transferring a gene from a jellyfish, whereas natural selection cannot bridge
the species barriers in this way. Likewise, nanotechnology may achieve in a few
decades things that nature never could.
After 2 020, sophisticated manipulations of viruses and cells will become
commonplace; integrated computer networb will have taken over many aspects of
our lives. Any forecasts for the mid-century are the realm of conjectures and
"scenarios." By then, nanobots could be a reality; indeed, so many people may try
to make nanoreplicators that the chance of one attempt triggering disaster would
become substantial. It is easier to conceive of extra threats than of effective
antidotes.
Such seemingly remote concerns should not divert attention from the diverse
vulnerabilities described in this chapter that are already with us, and growing. The
prospects should make us at least as "gloomy" as the pioneer atomic scientists were,
half a century ago, when the nuclear threat emerged. The gravity of a threat is its
magnitude multiplied by its probability: this is how we estimate our concern about
hurricanes, asteroid impacts, and epidemics. If we apply this calculus to the future
man-made risks that confront us, adding them all together, the Doomsday Clock
will shift ever closer to midnight.
5. PERPETRATORS AND PALLIATIVES
When just a few technically adept individuals can threaten human
society, abandonment of privacy may be the minimal price for maintaining
security. But would even a "transparent society" be safe enough?
WE ARE ENTERING AN ERA when a single person can, by one
clandestine act, cause millions of deaths or render a city uninhabitable for years,
and when a malfunction in cyberspace can cause havoc worldwide to a significant
segment of the economy: air transport, power generation, or the financial system.
Indeed, disaster could be caused by someone who is merely incompetent rather than
malign.
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These threats are growing for three reasons. First, the destructive and
disruptive capabilities available to an individual trained in genetics, bacteriology, or
computer networks will grow as science advances; second, society is becoming
more integrated and interdependent (internationally as well as nationally); and
third, instant communications mean that the psychological impact of even a local
disaster has worldwide repercussions on attitudes and behaviour.
The most conspicuous sub-national threat today comes from Islamic
extremists, motivated by traditional values and beliefs far removed from those
prevailing in the US and Europe. Other causes and grievances, also pursued
rationally and single-mindedly, can inspire equally fanatical acts by sectarian
groups or even "loners." Moreover there are some—and their numbers may grow in
the US—who have a tenuous hold on rationality, and could pose an even more
intractable threat if they had access to advancing technology.
Perpetrators and Palliatives
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Techno-lrrationality
Some optimists imagine that scientific or technical education reduces the
propensity towards extreme irrationality and delinquency. But many examples belie
this. The "Heaven's Gate" cult, though small in scale, was a portent of what can
happen in the technocratic West. A "cell" of cult members in California formed an
enclosed community, adept enough to finance themselves by designing web pages
for the Internet. But their technical competence, and genuine interest in space
technology and other sciences, was allied with a belief system that defied the ra-
tionality of scientific thought. Many cult members had actually castrated
themselves: they proclaimed on their web site the aspiration to transmogrify
themselves into "a physical body belonging to the true Kingdom of God—the
Evolutionary Level above human—leaving behind this temporal and perishable
world for one that is lasting and non-corruptible."
The arrival of the beings who they believed would transport them to this
higher plane would be heralded by a comet: "Comet Hale-Bopp's approach is the
'marker' we've been waiting for—the time for the arrival of the spacecraft from the
Level Above Human to take us home to Their World. We are happily prepared to
leave This World." When this comet, one of the brightest of the last decade,
approached closest to Earth, thirty-nine cult members, including their leader
Marshall Applewhite, aseptically and methodically took their lives.
Of course, collective suicides are nothing new: they date back at least two
thousand years. And they continue into modern times even in the west. The
Reverend James Jones led a messianic cult that retreated to a remote location in
South America—"Jonestown," in Guyana. In 1978 he instigated a mass suicide that
left all nine hundred cult members dead of cyanide poisoning.
Although modern technology allows instant worldwide communication, it
actually makes it easier to survive within an intellectual cocoon. The Heaven's Gate
group didn't need to go to the Amazonian forest to be isolated: being economically
self-sufficient via the Internet they could cut themselves off from any contact with
their actual physical neighbours, indeed with any "normal" people. Instead, their
beliefs were reinforced by selective electronic contact with other adherents of the
cult on other continents.
The Internet offers access, in principle, to an unprecedented variety of
opinions and information. Nonetheless, it could narrow understanding and
sympathies rather than broaden them: some people may choose to stay closeted
within a cyber-community of the likeminded. In his book republic.com, Cass
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Sunstein, a law professor at the University of Chicago, suggests that the
Internet is allowing all of us to "filter" our input, so that each person reads a "Daily
Me" customised to individual tastes and (more insidiously) purged of material that
may challenge prejudices. Rather than sharing experience with those whose
attitudes and tastes are different, many will in future "live in echo chambers of their
own design" and "need not come across topics and views that you have not sought
out. Without any difficulty, you are able to see exactly what you want to see, no
more and no less." It is too early to predict the effect of the Internet on mainstream
society (particularly in an international context). But there is a danger that it
promotes isolation and allows us (if we choose) more easily to evade the everyday
contacts that would unavoidably bring us up against conflicting views. Sunstein
discusses "group polarization," whereby those who interact only with the
likeminded have their prejudices and obsessions reinforced, and shift towards more
extreme positions.
The creed of "Heaven's Gate" was an amalgam of "new age" and science
fiction concepts. This cult was not unique; indeed, it is perhaps part of a resurgent
trend. The Raelians, headquartered in Canada, have over fifty thousand adherents in
more than eighty countries. Their founder and leader, Claude Voril-hon, originally
a motor-racing journalist, claimed in 1973 to have been abducted by aliens and
given information about how the human race was created using "DNA technology."
The Raelians are aggressively promoting a programme of human cloning that is not
only ethically problematic, but seems dangerously premature even to advocates of
this technique.
These cults may seem to come from the same "fringes" as UFO-watching
conspiracy theorists and the like. But in the US equally bizarre beliefs seem almost
part of the mainstream. Millions believe in "the Rapture"—when Christ swoops
back to Earth and transports true believers up to Heaven—or in the imminent
Millennium, as depicted in the Book of Revelation. The long-term future of this
planet and its biosphere are of no consequence to these Millenarian believers, some
of whom have achieved influence in the US. (During the Reagan administration,
environmental and energy policies were entrusted to James Watt, a religious
fundamentalist who held the office of secretary of the interior. He believed that the
world would end before the oil was used up and before we suffered the
consequences of global warming or deforestation, so it was almost our duty to be
profligate with Earth's divinely provided resources.)
Some of these cultists, like the members of "Heaven's Gate," threaten only
themselves. It would be unfair to demonize them all, or to conflate very disparate
beliefs. The resurgent cults are of course still a minuscule "sideshow" compared
with traditional ideologies. The zealotry of traditional religious enthusiasts, allied to
the single-issue fanaticism and ruthlessness of (for instance) the animal rights
extremists in the US and the UK, can be a threatening mix, especially when
accompanied by technical sophistication. The Internet allows groups to organise as
well as offering access to technical expertise. Our social and economic system is
becoming so brittle and interconnected that just a few individuals with this mindset
and access to modern technology can exert huge "leverage."
Even if one disruptive event could be coped with, a succession of them, their
psychological impact amplified by ever more pervasive communications media,
would be cumulatively corrosive. Awareness that such events could occur without
warning would exact a heavy social cost. In terrorist-prone localities you are
reluctant to venture on a bus if you fear there may be a suicide bomber among your
fellow passengers; you hesitate to do favours for a stranger; the privileged-seek
shelter
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in gated communities and enclaves. Future mega-terror could engender,
worldwide, this breakdown of community and trust. Obviously, these concerns
offer a further incentive for nations and the international community to minimise
the disaffection and injustices that give pretexts for grievance. But it is clear even
from recent US experience that the internal problem of nihilistic or apocalyptic
cults and aggrieved individuals is an intractable one.
Is Intrusive Surveillance the Least-Bad Safeguard?
One palliative would be acceptance of a complete loss of privacy, with the
deployment of novel techniques to keep tabs on us all. Universal surveillance is
becoming technically feasible, and could plainly be a safeguard against unwelcome
clandestine activities. Techniques such as surgically implanted transmitters are
already being seriously mooted to (for instance) monitor criminals on parole.
Subjecting all citizens to such treatment would be deeply unpalatable to most of us,
but if the threats escalated, we might become resigned to the need for such meas-
ures, and the next generation might find it less repugnant.
Orwellian surveillance, in traditional totalitarian style, would plainly be
unacceptable; unless encryption techniques kept pace, it would become ever more
intrusive with each technical advance. But suppose the surveillance was two-way,
and each of us could "spy" not only on the government but on everyone else. The
science fiction writer David Brin, in The Transparent Society, perhaps
provocatively, has argued that this "symmetrical" (but even more intrusive)
surveillance might be the least unacceptable way to ensure a safer future. It would
obviously require a change in mindset. But this may come about. Closed circuit TV
systems in public places are widespread in Britain,
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and generally welcomed as reassuring security measures, despite the loss of
privacy. More and more information about us—what we buy, where and when we
travel, and so forth—is already being recorded on "smart cards" used to purchase
merchandise or travel tickets, and whenever we use a mobile phone. I am surprised
how many of my friends willingly put intimate personal matters on web pages,
open to the world. So a "transparent society," in which deviant behaviour couldn't
escape notice, may be accepted by its members in preference to the alternatives.
Futuristic scenarios conjured up in Europe and the US may seem only
marginally relevant to the rest of the world, where poverty deprives most people of
the basic benefits of twentieth-century technology. But this transparency could
spread worldwide, as mobile phones and the Internet have done.
How would this spread affect relations between rich and poor nations? Few
non-Africans have direct knowledge ofsub-Saharan Africa except through films and
TV news reports. How will the US and European perceptions of the rest of the
world change when there can be immediate personal links? An optimistic view
would be that graphic "real time" evidence of personal need—of, for instance, the
AIDS sufferers who cannot afford even a dollar a day for basic treatment—would
stimulate individual generosity more effectively than the occasional messages and
photographs received by contributors to traditional programmes of charitable
sponsorship. But it seems unlikely that those who in the US retreat to gated
communities, insulated from the poor even in their own neighbourhoods, would
reach out to the desperate people of Africa. Even if they had the chance to befriend
them and maintain video contact, "compassion fatigue" could quickly set in.
Indeed, this may be another instance where the cyberworld leads to sharper social
segmentation.
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On the other hand, those in Africa and South Asia will have their relative
deprivation brought more insistently to their consciousness, especially if (as is
possible) access to cyberspace becomes cheaper to provide than basic sanitation,
food, and healthcare. The millions in impoverished countries will become less
quiescent, more aware of contrasts with more privileged areas, and with the
technical means to create major disruption. It is not just religious fundamentalism
that can trigger angry hostility to the West. If the entire developing world adopted
so-called Western values, the disadvantaged would be even more embittered at the
unequal benefits from globalisation and at a system of economic incentives that
provides superfluities for the rich rather than necessities for the destitute.
Can We Stay Human?
Up until now, it has been religion, ideology, culture, economics, and
geopolitics that have moulded societies. All these elements—in their immense
variety—have been the pretext for internal disputes and for wars. One unchanging
element over the centuries, however, has been human nature. But in the twenty-first
century drugs, genetic modification, and perhaps silicon implants into the brain will
change human beings themselves—their minds and attitudes, even their physiques.
Future genetically induced changes in the human population—though vastly
faster than any naturally occurring evolutionary changes—would still require a few
generations. But alterations in mood and mentality could spread even more rapidly
through entire populations via addictive drugs (or perhaps by electronic implants).
In Our Posthuman Future Francis Fukuyama argues that habitual and
universal use of mood-altering medications would
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narrow and impoverish the range of human character. He cites the use of
Prozac to counter depression, and of Ritalin to damp down hyperactivity in high-
spirited but otherwise healthy children: these practices are already constricting the
range of personality types that are considered normal and acceptable. Fukuyama
foresees a further narrowing, when other drugs are developed, that could threaten
what he regards as the essence of our humanity.
Indeed, injection of hormones that act directly on the brain will soon be able
to effect far more powerful and "targeted" changes in our personality than Prozac
and its ilk. The hormone PYY 3-36 has been shown to eliminate feelings of hunger,
by acting directly within the hypothalamus. One of the specialists in this technique,
Steve Bloom, of Hammersmith Hospital, London, has expressed concerns about
where this work could lead even within ten years: "If we can alter people's desire
for food, we can alter other deep-seated desires: the hypothalamus is also home to
brain circuits that influence sex drive and sexual orientation."
Fukuyama fears that drugs will become universally used to tone down
extremes of mood and behaviour, and that our species could degenerate into pallid
acquiescent zombies: society would become a dystopia resembling Aldous Huxley's
Brave New World. Even if we looked the same, we wouldn't be fully human.
Fukuyama would favour strong control of all mind-altering drugs. Prohibitions
need not be one hundred percent effective if the aim was to stave off the day when
all extreme personalities could be erased. There would be little overall impact on
national character if, despite regulation, a few delinquents gained access to drugs by
illicit tactics, or by travelling from their own country to one with laxer regulations.
But my worry is the obverse of Fukuyama's. "Human nature" encompasses a
rich variety of personality types, but these
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inclelude those who are drawn towards the disaffected fringe. The
destabilising and destructive influence of just a few such people will be ever more
devastating as their technical powers and expertise grow, and as the world we share
becomes more interconnected.
Thirty years ago the psychologist ȼ. ȿ Skinner foresaw, in his book Beyond
Freedom and Dignity, that some form of mind control might be needed to avoid a
breakdown of society; he argued that "conditioning" of the entire population was a
prerequisite for a society that its members were content to live in and that none
wished to destabilise.
Skinner was a behaviourist, and his mechanistic "stimulus-response" theories
are now discredited. But the issue that he highlighted is now more acute because
scientific advances allow even a single "aberrant" personality to cause widespread
havoc. If a present-day psychologist were emboldened to offer a panacea, it would,
ironically, resemble Fukuyama's posthuman nightmare: a population rendered
docile and law-abiding by "designer drugs" and genetic intervention that can
"correct" extremes of personality. Future brain science may even be able to
"modify" the personalities of people whose mindset might lead them to become
dangerously disaffected: an even more dystopian prospect.
In Philip K. Dick's science fiction fantasy Minority Report (now a Steven
Spielberg movie) the "pre cogs," mentally abnormal human beings specially bred
for the role, can identify those who are likely to commit future crime; potential
felons are then pre-emptively tracked down and imprisoned in vats. If our
propensities are indeed determined by genetics and physiology (and it is still
unclear to what extent they are) then identifying potential criminals may soon not
require psychic powers. There will then be growing pressures to institute this kind
of pre-emptive action in the real world, as a safeguard against the
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outrages—ever more calamitous with each technical advance— mat could be
wrought even by one delinquent individual.
Our civilisation, as Stewart Brand notes, is "ever more tightly linked and
ever more leveraged out over the abyss on an elaborate superstructure of highly
sophisticated technology, every part of which depends on the success of every other
part." Can its essence be safeguarded, without humanity having to sacrifice its
diversity and individualism? Must we, to survive, be cowed by a police state,
deprived of all privacy, or tranquillised into passivity?
Or could the threats be reduced by putting the brakes on potentially
threatening science and technology and even renouncing some areas of
scientific research completely?
6. SLOWING SCIENCE DOWN?
Twenty-first century sciences offer bright prospects, but have a dark
side as well. Ethical constraints on research, or relinquishment of potentially
threatening technologies, are difficult to agree and even tougher to
implement.
IN 2002 THE MAGAZINE WIRED, a glossy monthly with a focus on
computers and electronic gadgetry, inaugurated a series of "long bets." The idea
was to gather some predictions about future developments in society, science, and
technology, and thereby stimulate debate. The Internet guru Esther Dyson forecast
that Russia would achieve supremacy in the world's software industry within ten
years. Physicists staked bets on how long it would take to formulate a unified
theory of the fundamental forces—and indeed, on whether such a theory
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even exists. Another bet was that someone now alive would live to the age of
150, which is not implausible, given the rate of medical advance, but an odd bet
insofar as the prognosticators would not themselves expect to survive long enough
to witness the outcome.
I staked one thousand dollars on a bet: "That by the year 2020 an instance of
bioerror or bioterror will have killed a million people."
Of course, I fervently hope to lose this bet. But I honestly do not expect to.
This forecast involved looking less than twenty years ahead. I believe the risk
would be high even if there were a "freeze" on new developments, and the potential
perpetrators of such outrages or megaerrors had continuing access only to present-
day techniques. But of course, no subject is forging ahead faster than
biotechnology, and its advances will intensify the risks and enhance their variety.
Anxiety within the scientific community seems surprisingly muted. New
technologies can plainly offer colossal benefits, and most scientists have the
attitude that the downsides can often be best remedied by more (or differently
directed) technology; they are mindful of how much we might forgo if we did not
press ahead. In the early days of steam, hundreds of people died horribly when
poorly designed boilers exploded; likewise, aviation was hazardous in its early
days. Most surgical procedures, even if now routine, were risky and often fatal
when they were being pioneered. Every advance has proceeded by "trial and error,"
but the acceptable threshold can be set higher when the risk is voluntarily accepted
and the possible "upside" is large (as in the case of surgery). In an essay entitled
"The hidden cost of saying no," Freeman Dyson highlighted this issue. He
emphasised that the development and introduction of new drugs is inhibited—
sometimes to the detriment of many whose lives could be saved thereby—by the
prolonged and expensive safety trials required before approval.
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But there is a difference when those exposed to the risk are given no choice,
and don't stand to gain any compensating benefit, when the "worst case" could be
disastrous, or when the risk can't be quantified. Some scientists seem fatalistic
about the risks; or else optimistic, even complacent, that the more scarifying
"downsides" can be averted. This optimism may be misplaced, and we should
therefore ask, can the more intractable risks be staved off by "going slow" in some
areas, or by sacrificing some of science's traditional openness?
Scientists accept the need for controls on the way they work, and how their
discoveries are applied. Biological advances are opening up an ever increasing
number of potential applications—human cloning, genetically modified organisms,
and the rest—where regulation will be called for. Almost any applicable discovery
has a potential for evil as well as for good. No responsible scientist would echo the
words of H.G. Wells's fiendish Dr. Moreau: "I went on with this research just the
way it led me. That is the only way I ever heard of true research going. I asked a
question, devised some method of getting an answer, and got a fresh question. The
thing before you is no longer an animal, a fellow-creature, but a problem. ... I
wanted ... to find out the extreme limit of plasticity in a living shape."
Scientific Self-Restraint
Restraint is obviously justified if the experiments themselves pose a risk: for
instance, by creating dangerous pathogens that might escape, or by generating
extreme concentrations of energy. Scientists sometimes abide by self-imposed
moratoriums on specific lines of research. A precedent for this was the declaration
put forward in 1975 by prominent molecular biologists to refrain from some types
of experiments rendered possible by
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the then-new technique of recombinant DNA. This followed a meeting at
Asilomar, California, convened by Paul Berg, of Stanford University. The Asilomar
moratorium soon came to seem unduly cautious, but that doesn't mean that it was
unwise at the time, since the level of risk was then genuinely uncertain. James
Watson, codiscoverer of DNA's double helix, regards this attempt at self-regulation
as, in retrospect, a mistake. (Watson is generally "bullish" about the applications of
biotechnology, believing that we should be uninhibited about using new knowledge
of genetics to "improve" humanity. He has asked rhetorically "If biologists won't
play God, who will?"). But another Asilomar participant, David Baltimore, remains
proud of the episode: in his view it was right "to engage society in thinking about
the problems, because we know that society could block us from realising the
tremendous benefits of this work unless we square with them and lead them in
thinking through the problems."
The Asilomar episode seemed an encouraging precedent. It showed that an
international group of leading scientists could agree to a self-denying ordinance,
and that their influence on the research community was sufficient to ensure that it
was implemented. There are now even more reasons for exercising restraint, but a
voluntary consensus would be far harder to achieve today: the community is far
larger, and competition (enhanced by commercial pressures) is more intense.
In many countries there are formal guidelines and licensing requirements for
animal experimentation, motivated by humane concerns. However, there is a
"penumbra" of experiments that, even though neither cruel nor dangerous, prompt a
reflex of revulsion that leads some to urge broader regulations. Bioethicists use the
term "yuck factor" to denote an emotional recoil from violations of what we
perceive as the natural order. This reaction sometimes just reflects an unthinking
conservatism that erodes as we become familiar with a new technique: kidney
transplants provoked this response when first introduced but are now widely
accepted; indeed, even cornea transplants once did. Newspaper pictures of a mouse
that had been implanted with a template on which tissue had grown in the form of a
human ear, almost as large as the rest of its body, prompted an exaggerated "yuck!"
reaction, despite assurances that the mouse was itself relaxed about its treatment
and oblivious to the way it looked.
I personally have a "yuck!" response to invasive experiments that modify
how animals behave. Physiologists at the State University of New York's medical
centre in Brooklyn implanted electrodes into rats' brains. One electrode stimulated
the cerebral "pleasure centre"; two other electrodes activated the regions which
process signals from its left and right whiskers. This simple procedure transformed
the animals into "roborats" that could be\steered to left or right, and forced to
behave in patterns that would-seem to go squarely against their instincts. These
procedures were not necessarily cruel to the rats, and in some sense no different
from the way a horse or ox is harnessed or driven. Nonetheless, such experiments
could presage intrusive modifications (of humans as well as of animals) that
undercut what many feel should be their intrinsic nature; the same reaction will be
engendered by more sophisticated hormonal techniques for modifying thought
processes.
Perhaps only a minority react in this disproportionate way against these
mouse and rat experiments. However, some procedures that may soon be possible,
could trigger such widespread revulsion that there will surely be pressure to ban
them: for instance, the "design" of insentient animals who (it would then be argued)
would have the moral status of vegetables and so could be treated appallingly with
no ethical compunctions at all. (The food industry would then be relieved of
pressure to
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abandon its cruelly intensive treatment of factory-farmed animals). Brainless
hominoids whose organs could be harvested as spare parts would seem, ethically,
even more problematic. On the other hand, transplanting organs from pigs or other
animals into humans should raise no more ethical concerns than meat-eating,
though this technique (xenotransplantation) will perhaps be banned—irrespective of
ethical judgements—because of the risks that new animal diseases could be
introduced into the human population. Using stem cells to grow a replacement
organ in situ would seem much the most acceptable alternative to transplant
surgery, which often involves waiting tensely, with ambivalence if not eagerness,
for a car crash or similar misfortune to provide a suitable "donor."
Animal cloning techniques may soon become routine, but attempts to clone
human beings provoke a widespread "yuck!" response. The Raelian cult is
rumoured already to have hundreds of cloned embryos. Responsible scientists
would oppose any cloning attempts because of the likelihood that even if a
pregnancy proceeded to full term, the resulting infant could be devastatingly
damaged. Despite the general ethical objections, and the high chance of defective
births, it is surely only a matter of years before the birth of the first cloned human.
Choices on how science is applied—to medicine, the environment, and so
forth—should be debated far beyond the scientific community. This is one reason
why it is important that a wide public should have a basic feel for science, knowing
at least the difference between a proton and a protein. Otherwise, such debate won't
get beyond slogans, or will be conducted at megaphone level via sensational
headlines in tabloid newspapers. The views of scientists should not have special
weight in deciding questions that involve ethics or risks: indeed, such judgements
are best left to broader and more dispassionate groups. One welcome feature of the
publicly funded Human
Genome Project was that part of the budget was specifically allocated to
discussion and analysis of the project's ethical and societal impact.
The Paymasters of Science
Scientific research, and our motives for pursuing it, cannot be separated from
the social context in which such research is carried out. Science underpins modern
society. But equally, society's attitudes determine what kind of science is found
interesting, and what projects gain favour with governments or commercial patrons.
There are several examples just from sciences I am myself involved in. Huge
machines for studying subatomic particles gained government funding because they
were spearheaded by physicists who had achieved clout through their role in World
War II. The sensors used by astronomers to detect faint emission from distant stars
and planets were devised to enable the US military to detect Vietnamese in the
jungle; they are now used in digital cameras. And expensive scientific projects in
space—the probes that have landed on Mars and given close-up pictures of Jupiter
and Saturn—ride along on a huge space programme that was initially driven by
superpower rivalry during the Cold War. The Hubble Space Telescope would have
cost even more had it not shared some development costs with spy satellites.
Because of extraneous influences like this—and one could come up with
equivalent lists in other scientific fields—scientific effort is deployed suboptimally.
This seems so whether we judge in purely intellectual terms, or take account of
likely benefit to human welfare. Some subjects have had the "inside track" and
garnered disproportionate resources. Others, such
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as environmental research, renewable energy sources, and biodiversity
studies, deserve more effort. Within medical research the focus is
disproportionately on cancer and cardiovascular studies, the ailments that loom
largest in prosperous countries, rather than on diseases endemic in the tropics.
Most scientists nonetheless regard knowledge and understanding as worth
attaining for their own sake, believing that "pure" research should be untrammelled,
provided that it is safe and there are no ethical objections. But is that simplistic?
Are there areas of academic research—the kind of science done in university
laboratories—that the wider public should try to restrain, because of unease about
where they might lead? The surest safeguard against a new danger would be to
deny the world the basic science that underpins it.
All countries give enhanced support, on strategic grounds, to sciences that
promise valuable spin-off. (Molecular biology is favoured over black hole research,
for example; I am myself involved with the latter, but nonetheless this
discrimination doesn't seem unfair to me.) But does the converse follow: should
support be withdrawn from a line of "pure" research, even if it is undeniably
interesting, if there is reason to expect that the outcome will be misused? I think it
should, especially since the present allocation among different sciences is itself the
outcome of a complicated "tension" between extraneous factors. Of course,
scientists cannot be completely stopped from thinking and speculating: their best
ideas often come unbidden, during leisure hours. But any academic scientist whose
grant has been stopped is aware that funding cuts can slow down a line of research,
even if they could never halt it completely,
Whenever an investigation holds short-term promise of lucrative spin-off,
public funding isn't needed, because commercial sources will step in to bankroll it:
only government regulation could then stop such research. Such regulation would
also constrain how private benefactors choose to dispense their resources. Wealthy
individuals can distort research—one American gave Texas A&M University five
million dollars for research on cloning because he wanted to clone his elderly dog.
To put effective brakes on a field of research would require international consensus.
If one country imposed regulations, the most dynamic researchers and enterprising
companies would migrate to another that was more sympathetic or permissive. This
is happening already in stem cell research, where some countries, particularly the
UK and Denmark, have established relatively permissive guidelines, and are
thereby attracting a "brain gain." By offering a still more enticing regime to
researchers and to their fledgling biotech industry, Singapore and China aim to
leapfrog the competition.
The difficulty with a dirigiste policy in science is that the epochal advances
are unpredictable. I already noted that X rays were an accidental discovery by a
physicist, not the outcome of a crash medical program to see through flesh. As
another example, a nineteenth-century project to improve reproduction of music
would have led to an elaborate and mechanically intricate orchestrion, but would
have brought us no closer to the techniques actually used in the twentieth century.
These techniques were the outcome of curiosity-driven research on electricity and
magnetism by Michael Faraday and his successors. In more recent times, the
pioneers of lasers had little concept of how their invention would be applied (and
certainly did not expect that one of the first uses would be for operations to repair
detached retinas).
We can ask of any innovation whether its potential is so scary that we should
be inhibited in pressing on with it, or at least impose some constraints.
Nanotechnology, for instance, is likely to transform medicine, computers,
surveillance, and other practical areas, but it might advance to a stage at which a
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replicator, with its associated dangers, became technically feasible. There
would then be the risk, as there now is with biotechnology, of a catastrophic
"release" (or that the technique could be used as a "suicide" weapon); the only
countermeasure would be a nanotech analogue of an immune system. To guard
against this, Robert Freitas suggests an Asilomar-style moratorium: artificial life
should be studied only via computer experiments, rather than by experimenting
with any kind of "real" machines, and there should be a ban on developing
nanomachines that can reproduce in a natural environment. Similar concerns might
be raised about superintelligent computer networks and other extrapolations of
present technology.
Concealment or Openness?
Rather than aiming to slow down a research area, can the risks be stanched
by selectively denying new knowledge to those who seem likely to misapply it?
Governments have always kept much of their defence-related work secret. But
research that is not so classified (nor kept confidential for commercial reasons) has
traditionally been made accessible to everyone. In 2002 the US government
proposed that scientists themselves should restrict the dissemination of new
research that, though not classified, is sensitive and could be misapplied: this was
such a departure from the usual ethos that it caused controversy within the
American scientific community.
What does a university do if a seemingly qualified student with a lavish grant
but suspicious provenance wants to enrol for a Ph.D. in nuclear engineering or
microbiology? By attempting to obstruct the training of potential delinquents we
could at most impose a modest delay in the diffusion of new ideas, especially since
"high-risk" individuals cannot be reliably identified
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anyway. Some may say that anything that applies the brakes, even
marginally, is worthwhile. Others might argue that since the capability will spread
anyway, it might even be better to be networked to as many ex-students as possible.
There is then less chance that a substantial illicit project could be pursued without
news leaking out via personal contacts. Maximum openness in communications,
and a high rate of international migration, would render even small-scale
clandestine projects harder to conceal. The international flow of students and
scholars is in practice restricted by national policies on entry visas, but if the
decisions were left to universities, I think most would take an open attitude with
regard to students, while imposing a stringent filter on more senior scientific
visitors.
One measure already being discussed would be an international agreement to
make procurement or possession of dangerous pathogens, anywhere, an individual
criminal offence in any country—just as hijacking of aircraft now is—and to foster
a culture where "whistle blowing" is rewarded. A prime advocate of this campaign
is Harvard professor Matthew Meselson, a leading expert on biological weapons.
Scientists are the critics of their subject, as well as the creators; quality
control is enforced by the "peer review" that precedes publication of any new
discovery in an academic journal. This is a safeguard against unmerited or
exaggerated claims. But this copybook procedure is being violated more and more
often, because of commercial pressures, or sometimes just intense academic rivalry.
Newsworthy discoveries are trumpeted, via press releases or conferences, before
they have been reviewed. In contrast, other discoveries are kept private, for com-
mercial reasons. And scientists themselves face a dilemma when they are
researching "sensitive" topics: lethal viruses, for instance.
One of the most spectacular departures from scientific
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norms occurred in 1989 when Stanley Pons and Martin Fleischmann, then
working at the University of Utah, claimed to have generated nuclear power at
ordinary room temperature, using a tabletop apparatus. If credible, the claim fully
merited all the hype it aroused: "cold fusion" would have offered the world an
unlimited supply of cheap and clean energy. It would have ranked as one of the
great discoveries of the century—indeed, one of the most momentous
breakthroughs since the discovery of fire.
But technical doubts quickly surfaced. Extraordinary claims demand
extraordinary evidence, and in this case the evidence proved far from robust.
Inconsistencies were discerned in Pons and Fleischmann's claims; experimenters in
several other laboratories tried to reproduce the phenomenon, but without success.
Most scientists were sceptical and suspicious right from the start; within a year
diere was a general consensus that the results were misinterpreted, though even
today there remain a few "believers."
A similar episode in 2002 was handled better. A group led by Rusi
Taleyarkhan, a scientist at the Oak Ridge National Laboratory, was investigating a
puzzling effect known as "sonolumi-nescence": when intense sound waves pass
through a bubbly liquid, the bubbles get compressed and emit flashes of light. The
Oak Ridge researchers claimed to have squeezed the imploding bubbles by a clever
technique to such high temperatures that they became hot enough to trigger nuclear
fusion, a fleetingly transient and miniaturised version of the process that keeps the
Sun shining and generates the power in a hydrogen bomb. Not even all their
colleagues at Oak Ridge believed them: the claim didn't violate "cherished beliefs"
as much as cold fusion did, but still seemed implausible. But Taleyarkhan
submitted a paper to the prestigious journal Science. Despite the scepticism of the
referees, the editor chose to publish the
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paper but with an editorial warning that it was controversial. This decision at
least ensured that the claim got maximal scrutiny.
The "cold fusion" fiasco did no great harm in the long run, except to the
personal reputations of Pons and Fleischmann, and those who had jumped
uncritically on their bandwagon. And the validity of Taleyarkhan's claims will soon
be settled via debate and independent repetitions of his experiments. Any
potentially epochal claim, provided it is openly announced, will be guaranteed to
attract wide scrutiny from the international community of experts. So it doesn't
matter a great deal if formal peer review is bypassed, provided that there is no
impediment to openness.
Suppose, however that-claim as extraordinary as Pons and Fleischmann's had
come from senior scientists in a laboratory whose mission was military or
commercially confidential research. What would then have happened? It is very
unlikely that the work would ever have reached the public gaze: once the
unprecedented economic and strategic importance of the "discovery" was
appreciated by those in charge, a massive secret research programme would have
got underway, consuming huge resources and shielded from open scrutiny.
Something very like this actually happened in the 1980s. The Livermore
Laboratory, one of the two giant US laboratories involved in developing nuclear
weapons, had a large secret programme aimed at producing x-ray lasers. This effort
was funded as part of President Reagan's Strategic Defence Initiative ("star wars")
project. The concept involved lasers in space that would be triggered by a nuclear
explosion; in the microsecond before being vaporised the device was supposed to
create intense "death rays" that could destroy incoming enemy missiles.
Independent experts were almost uniformly scathing in their judgements. But it was
the brainchild of Edward Teller
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and his proteges: working in a "closed" environment, with access to vast
resources from the Pentagon, they were able to commit literally billions of dollars
to this abortive "x-ray laser" scheme. Had one of Teller's scientists come up with a
new source of energy, one can well imagine persuasive arguments, behind closed
doors, that the national interest demanded a "crash" programme. In these examples,
secrecy leads to waste, and to misdirection of effort. Even worse would be a
clandestine project that actually posed risks that the experimenters were unaware
of, or were downplaying, but which would have prompted most outside scientists to
call for a halt.
"Fine-Grained Relinquishment"
An influential voice in favour of "going slow" is Bill Joy, co-founder of Sun
Microsystems, and the inventor of the Java computer language. It was surprising to
find such heartfelt unease expressed—in Wired magazine, of all places—by one of
the heroes of cybertechnology, and his article "Why the Future Doesn't Need Us,"
published in 2000, attracted wide comment. The London Times ran an editorial
likening it to the famous 1940 memorandum from the physicists Robert Frisch and
Rudolf Peierls that alerted the UK government to the feasibility of an atomic bomb.
Joy's gaze is fixed on the far horizon. Rather than being fearful of where
genetics and biotechnology might be leading us in the present decade—
misapplications of genomics, the risk of bioterror by individuals, and so forth—
Joy's disquiet focuses on the more remote threats of physics-based technologies. He
is especially worried about the "runaway" consequences that may ensue when
computers and robots surpass human capabilities. He isn't primarily concerned
about malign misuse of the new technology, simply that genetics, nanotechnology,
and robotics (GNR technologies) may develop uncontrollably and "take us over."
Joy's recipe is to "relinquish" the research and development that could make
these threats real: "If we could agree, as a species, what we wanted, where we were
headed, and why, then we would make our future much less dangerous—then we
might understand what we can and should relinquish. Otherwise, we can easily
imagine an arms race developing over GNR technologies, as it did with [nuclear]
technologies in the twentieth century. This is perhaps the greatest risk, for once
such a race begins, it's very hard to end it. This time—unlike during the Manhattan
Project—we aren't in a war, facing an implacable enemy that is threatening our
civilisation; we are driven, instead, by our habits, our desires, our economic system,
and our competitive need to know."
As Joy realises, it wouldn't be easy to achieve a consensus that a specific
type of research was so potentially dangerous that we should forgo it; human beings
can seldom "agree, as a species"—the phrase Joy uses—even on what seem more
urgent imperatives. Indeed, even a single enlightened individual would find it hard
to know where to draw the line in research. So can relinquishment be sufficiently
"fine grained" to discriminate between benign and hazardous projects? Novel tech-
niques and discoveries will generally have manifest short-term usefulness, as well
as being steps towards Joy's long-term nightmare. The same techniques that could
lead to voracious "nanobots" might also be needed to create the nanotech analogue
of vaccines that could immunise against them. If clandestine groups were pursuing
dangerous research, it would be harder to devise countermeasures if nobody else
had the relevant expertise.
Even if all the world's scientific academies agreed that some
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specific lines of inquiry had a disquieting "downside" and all countries, in
unison, imposed a formal prohibition, then how effectively could it be enforced?
An international moratorium could certainly slow down particular lines of research,
even if they couldn't be stopped completely. When experiments are disallowed for
ethical reasons, enforcement with ninety-nine percent effectiveness, or even just
ninety percent, is far better than having no prohibition at all; but when experiments
are exceedingly risky, enforcement would need to be close to one hundred percent
effective to be reassuring: even one release of a lethal virus could be catastrophic,
as could a nanotechnology disaster. Despite all the efforts of law enforcers, millions
of people use illicit drugs; thousands peddle them. In view of the failure to control
drug smuggling or homicides, it is unrealistic to expect that when the genie is out of
the bottle, we can ever be fully secure against bioerror and bioterror: risks would
still remain that could not be eliminated except by measures that are themselves
unpalatable, such as intrusive universal surveillance. My pessimism is nearer-term,
and in some ways deeper, than Bill Joy's. He is concerned to stave off the day when
superintel-ligent robots could take over from us, or the biosphere could crumble
into "grey goo." But before these futuristic capabilities are attained, society could
be dealt a shattering blow by misapplication of technology that exists already, or
that we can confidently expect within the next twenty years. Ironically, the only
compensating cheer is that if these shorter-term fears were realised, the
hyperadvanced technology necessary for nanomachines and superhuman computers
would suffer a perhaps irreversible setback, thereby safeguarding us against the
scenarios that most trouble Bill Joy.
7. BASELINE NATURAL HAZARDS
Asteroid Impacts
We are at greater risk from a massive asteroid than from plane
crashes, but the mounting human-induced threats are far more disquieting
than any natural hazard.
IN JULY 1994, MILLIONS OF PEOPLE WATCHED, via the Internet,
telescopic images of the largest and most dramatic "splashes" ever witnessed.
Fragments of a large comet crashed into Jupiter; dark spots larger than the entire
Earth, each a "scar" from a massive impact, were visible on that giant planet's
surface for several weeks afterwards. The shattered comet, named Shoemaker-Levy
after its discoverers, had been observed, in the previous year, to break up into about
twenty pieces. Astronomers calculated that the fragments were on
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trajectories that would hit Jupiter, and geared up to watch the impacts at the
predicted time.
This episode highlighted the vulnerability of our own planet to impacts of a
similar kind. Earth presents a smaller target than Jupiter, the giant of our solar
system, but comets and asteroids routinely come close enough to be a danger.
About sixty-five million years ago Earth was hit by an object about ten kilometres
across. The resultant impact released as much energy as a million H-bombs; it
triggered mountain-shattering earthquakes around the world, and colossal tidal
waves; it threw enough debris into the upper atmosphere to block out the Sun for
more than a year. This is believed to have been the event that wiped out the
dinosaurs. Earth still bears its scar: this momentous impact scoured out the
Chicxulub crater in the Gulf of Mexico, nearly two hundred kilometres across.
Two separate classes of "rogue" objects hurtle around our solar system:
comets and asteroids. Comets are made largely of ice, along with frozen gases such
as ammonia and methane: they are often described as "dirty snowballs." Most
comets spend nearly all their time, invisible to us, lurking in the cold outermost
reaches of the solar system, far beyond even Neptune and Pluto; but sometimes
they plunge inward towards the Sun on near-radial trajectories, getting warm
enough for some ice to be vaporised, liberating gas and dust that reflects sunlight to
create the conspicuous "tail." Asteroids, less volatile objects than comets, are
composed of rocky material and move in near-circular orbits around the Sun. Most
of them stay a safe distance from Earth, between the orbits of Mars and Jupiter. But
some, the so-called near-Earth objects (NEOs), follow orbits that can intersect
Earth's.
These NEOs range widely in size, from "minor planets" more than one
hundred kilometres across, right down to mere pebbles. A ten-kilometre asteroid,
harbinger of worldwide ca-
tastrophe and major extinctions, is expected to hit Earth once every only fifty
to one-hundred-million years. The Chicxulub impact, sixty-five million years ago,
may have been the most recent event of this magnitude. Two other similarly vast
craters, one in Woodleigh, Australia, and another at Manicouagan, near Quebec, in
Canada, could be the aftermaths of comparable impacts 200 to 250 million years
ago. Perhaps one of these caused the greatest extinctions of all, at the
Permian/Triassic transition 250 million years ago. (At the time of these impacts, the
Atlantic Ocean had not opened up, and most of Earth's land mass was part of a
single continent, known as Pangaea.)
Smaller asteroids (and less devastating impacts) are much more common:
NEOs-ene kilometre across are a hundred times more numerous than the extinction-
triggering ten-kilometre asteroids; one-hundred-metre-sized bodies are probably a
hundred times more numerous still. The well-known Bar-ringer crater in Arizona
was carved out by an asteroid about a hundred metres across, which hit about fifty
thousand years ago; a similar crater in Wolfe Creek, Australia, is about three
hundred thousand years old. NEOs fifty metres across seem to hit Earth once per
century. In 1908, the Tunguska meteorite devastated a remote part of Siberia. It was
moving so fast, up to forty kilometres per second, that its impact packed the punch
of a forty-megaton explosion. It vaporised and exploded high in the atmosphere,
flattening thousands of square kilometres of forest but leaving no crater.
A Low Risk, but Not Negligible
We do not know whether a large dangerous NEO "with our name on it" is
destined to hit in the coming century. However, we know enough about how .many
asteroids there are on
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Earth-crossing orbits to be able to quantify the probability. The risk isn't
large enough to keep anyone awake at night, but it isn't completely negligible
either. There is a fifty percent risk of a Tunguska-scale impact somewhere on Earth
this century. But most of Earth's surface is either covered with oceans or sparsely
populated, so the chance of an impact on a densely populated region is far smaller:
but such an event could cause millions of fatalities.
In the world as a whole, the risk from floods, tornados and earthquakes
looms larger. (Indeed the worst localised natural catastrophe that could be deemed
probable in this century would be an earthquake in Tokyo or perhaps in Los
Angeles, where the immediate devastation would have a longer-term "fallout" for
the world's economy.) However, for Europeans and North Americans outside the
areas most prone to earthquakes or hurricanes, asteroid impact is actually the
number-one natural hazard. The dominant risk is not from Tunguska-scale events,
but from rarer impacts that would each devastate a larger area.
If you are now, say, twenty-five years old, your future life expectancy is
about fifty years. The chance of being a victim of a massive asteroid impact is
therefore roughly the probability that one happens in the next fifty years. Before
that time is up, there is about one chance in ten thousand that an asteroid half a
kilometre across will crash in to the North Atlantic, causing giant tsunamis (tidal
waves) that would destroy the North American and European seaboard; or into the
Pacific, where it would have similar consequences for the coasts of East Asia and
the Western US. The probability that we'll end our lives (along with many millions
of others) in such an event is about the same as the average person's risk of dying in
an air crash— somewhat higher, indeed, if we live near a coast, where we are
vulnerable to smaller tsunami.
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It is a minor risk, but no lower than other hazards that governments take
measures to guard against or ameliorate. A recent report on NEOs commissioned
by the British government presented the situation like this: "If a quarter of the
world's population were at risk from the impact of an object of i kilometre diameter,
then according to current safety standards in use in the United Kingdom, the risk of
such casualties, even if occurring on average once every 100,000 years, would
significantly exceed a tolerable level. If such risks were the responsibility of an
operatov of an industrial plant or other activity, then that operator would be equired
to take steps to reduce the risk."
By discovering and tracking the most dangerous Earth-crossing NEOs, we
could in principle have years of warning of any major catastrophe. Were an impact
in mid-Atlantic to be forecast, then a massive evacuation of coastal areas could save
tens of millions of lives, even if we couldn't do anything to divert the incoming
object. The international community spends billions of dollars a year on weather
forecasting, and can thereby predict hurricanes; it would seem worth a few millions
to ensure that a (much more unlikely but far more devastating) giant tsunami—as
portrayed in the movie Deep Impact—didn't catch us unawares.
Reducing the Risk?
There is another motive for surveying and cataloguing all NEOs: in the long
run, it may be possible to deflect rogue objects away from Earth, but very
accurately known orbits are a prerequisite, and accuracy will not be achieved unless
these objects have been tracked for a long time beforehand. Arthur C. Clarke's
novel Rendezvous with Rama describes how a Tunguska-
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type event wipes out northern Italy. (The year Clarke picked for this
catastrophe was 2077, and the date, coincidentally, September 11.) "After the initial
shock, mankind reacted with a determination and a unity that no earlier age could
have shown. Such a disaster might not occur again for a thousand years—but it
might occur tomorrow. Very well; there would be no next time. No meteorite large
enough to cause catastrophe would ever again be allowed to breach the defences of
Earth. So began Project Spaceguard."
"Spaceguard"-type projects, whereby we can not merely be forewarned but
even protected against asteroid impacts, need not remain science fiction: they could
be implemented within fifty years. If we knew several years in advance that an
NEO was on course to hit Earth, nothing could be done about it today. But within a
few decades we might have the technology needed to divert the trajectory enough
to ensure that the "rogue" object posed no danger. The longer the advance warning
we had of an impending impact, the smaller would be the orbital nudge needed to
change its course so that it missed us. But it would be imprudent even to attempt
such an enterprise without knowing a great deal more about what asteroids are
made of than we now do. Some are solid boulders; but others (perhaps most) may
be loosely packed piles of rock held together only by "stickiness" and by their very
weak gravity. In the latter case, attempts to push an asteroid off course (especially
by drastic methods such as a nuclear explosion) could shatter it into pieces, which
would pose an even greater aggregate risk to Earth than the original single body
did.
Comets are harder to deal with. A few (like Halley's comet) return repeatedly
and follow well-charted orbits, but most approach us "cold" from deep space,
giving no more than a year's warning. Also, their orbits are somewhat erratic
because gas squirts from them, and fragments break off in unpredictable
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ways. For these reasons, comets pose an intractable and perhaps irreducible
risk to us.
A numerical index of the seriousness of unlikely catastrophes such as
potential asteroid impacts was introduced by Richard Binzel, a professor at MIT.
This was adopted at an international conference in Turin (Torino) and has become
known as the Torino scale. It resembles the familiar Richter scale for earthquakes.
However, an event's ranking on the Torino scale takes account of its likelihood as
well as its magnitude: the seriousness of a potential threat depends on its
probability, multiplied by the amouBLof^devastation that would ensue if it actually
happened. The scale runs from 1 to 10. A fifty-metre asteroid, like the one that
exploded above Siberia in 1908, would have rank 8 on the scale if it were certain to
hit us; a one-kilometre asteroid would have rank 10 if it were certain to hit, but only
8 if its orbit was so poorly known that we could merely predict that it would pass
somewhere within a million kilometres of Earth. Earth is only 12,750 kilometres
across, so the probability of hitting the "bull's-eye" would then be about one in ten
thousand.
The Torino number assigned to a particular event can change as our evidence
mounts. For example, the path of a hurricane may initially be hard to predict; as it
progresses, we can forecast with ever-increasing confidence whether it will pass
over a populous island or whether it will miss. Likewise, the longer we track an
NEO, the more precisely we can predict its future trajectory. Large asteroids are
regularly identified that on the basis of a crudely determined orbit could endanger
Earth. But when their orbits have been pinned down more exactly, we generally
become confident that they will miss, so their ranking on the Torino scale drops
towards zero. However, in the minority of cases where the area of uncertainty
shrinks, but Earth remains within it, we would have reason to
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become even more worried, and the Torino number would rise, perhaps from
8 towards 10.
Experts in NEO impacts have now devised a more refined index, called the
Palermo scale, which takes account of how far in the future the possible impact
would occur. This is a better measure of how concerned we should be. For instance,
if we knew that a fifty-metre asteroid would hit Earth next year, that would rate
high on the Palermo index, but if the impact of that particular object were forecast,
with an equally high confidence level, for (say) the year 2890, it would not raise
our anxiety level at all. This is not simply because we discount future risks (espe-
cially if they are so far ahead that we are all dead) but because the law of averages
leads us to expect several Tunguska-scale events, caused by similarly sized
asteroids, before that time.
Modest efforts are worthwhile to monitor the few thousand largest NEOs
that could pose a threat. If the conclusion was that none of them would hit Earth in
the next fifty years, we would have gained a degree of reassurance that would be
worth the modest collective investment involved. If the outcome were less
reassuring, we could at least prepare ourselves; moreover, if the predicted impact
were (say) fifty years from now, there might be enough time to develop the
technology to deflect the rogue object. It is also worth improving statistical
knowledge of the smaller objects, even though we could not expect to have much
forewarning if one of these were heading towards a direct hit with Earth.
Supereruptions
Apart from the ever-present hazard from impacting asteroids and comets
there are other natural catastrophes even harder to predict far ahead, and that are
even more difficult to prevent or stave off: extremely violent earthquakes and
volcanic eruptions, for instance. The latter include a rare class of "supereruptions,"
thousands of times larger than the eruption of Krakatoa in 1883, that would propel
thousands of cubic kilometres of debris into the upper atmosphere. A crater in
Wyoming, eighty kilometres across, is a relic of such an event about a million
years, ago. Rather closer to the present, a supereruption in northern Sumatra
seventy thousand years ago left a one-hundred-kilometre crater and ejected several
thousand cubic kilometres of ash, enough to have blocked out the Sun for a year or
more.
Two aspects of these violent natural catastrophes are, however, somewhat
reassuring. Firstly, massive asteroid impacts and colossal volcanic eruptions are so
rare that reasonable people aren't deeply anxious about them, nor preoccupied with
them (though, were it technically feasible, it would be worth a substantial
investment to reduce the risk further). Secondly, they are not getting any worse: we
may be more aware of them than earlier generations were (and society is certainly
more risk-averse than it was), but nothing humankind does is likely to increase the
risk of asteroid impacts, nor of volcanic super-eruptions.
They serve therefore as a "calibration" against the fast-growing human-
induced risks to the environment, which could according to pessimistic scenarios
become thousands of times larger.
8. HUMAN THREATS TO EARTH
Environmental changes induced by human activities, still poorly
understood, may be graver than the "baseline" threats from earthquakes,
eruptions, and asteroid impacts.
IN HIS BOOK THE FUTURE OF LIFE, E.O. Wilson sets the scene with an
image that highlights the complex fragility of "Spaceship Earth": "The totality of
life, known as the biosphere to scientists and creation to the theologians, is a mem-
brane of organisms wrapped around Earth so thin it cannot be seen edgewise from a
space shuttle, yet so internally complex that most species composing it remain
undiscovered."
Human beings are depleting the variety of Earth's plant and animal life.
Extinctions are, of course, intrinsic to evolution and natural selection: fewer than
ten percent of all the species that ever swam, crawled, or flew are still on Earth
today. An
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extraordinary procession of species (almost all now extinct) has traced the
higgledy-piggledy path by which natural selection led from unicellular organisms to
our present biosphere. For over a billion years, primitive "bugs" exhaled oxygen,
transforming the young Earth's poisonous (to us) atmosphere and clearing the way
for complex multicellular forms of life—relative newcomers—and for our eventual
emergence.
It needs an imaginative leap to grasp geological time spans, and how
colossally prolonged they are compared to hominoid history, which is in turn far
longer than recorded human history. (In popular culture these huge disjunctions are
sometimes elided, as in old movies like A Million Years ȼɋ, portraying Raquel
Welch cavorting among the dinosaurs.)
We know from fossils that a cornucopia of swimming and creeping things
evolved during the Cambrian era 550 million years ago leading to a vast
diversification of species. The next 200 million years saw the greening of the land,
offering a habitat for exotic creatures: dragonflies as big as seagulls, millipedes a
yard long, giant scorpions and squid-like sea monsters. Then came the dinosaurs.
Their sudden demise sixty-five million years ago opened the way to mammals, to
the emergence of apes and ourselves. A species lasts for millions of years; even the
most rapid bursts of natural selection generally take thousands of generations to
change the appearance of any species. (Catastrophic events can, of course, induce
drastic changes in animal populations; asteroid impacts, for instance, can trigger
sudden extinctions.)
The Sixth Extinction
Geological records reveal five great extinctions. The largest of all happened
at the Permian/Triassic transition around 250 million years ago; the second largest,
65 million years ago, wiped out the dinosaurs. But human beings are perpetrating a
"sixth extinction" on the same scale as earlier episodes. Species are now dying out
at one hundred or even one thousand times the normal rate. Before Homo sapiens
came on the scene, about one species in a million became extinct each year; the rate
is now is closer to one species in a thousand. Some species are being killed off
directly; but most extinctions are an unintended outcome of human-induced
changes in habitat, or of the introduction of nonindigenous species into an
ecosystem.
Biodiversity is being eroded. Extinctions are deplorable not just for aesthetic
and sentimental reasons, attitudes engendered disproportionately by the so-called
charismatic vertebrates— the tiny minority of species that are feathered, furry, or
grandly oceanic. Even at the most utilitarian level, we are destroying the genetic
variety that may prove of value to us. As Robert May says, "We are burning the
books before we've learnt to read them." Most species have not yet even been
catalogued. Gregory Benford has proposed a Library of Life project, an urgent
effort to gather, freeze, and store a sample of the complete fauna of a tropical rain
forest, not as a substitute for conservation measures, but as an "insurance policy."
Threats to the biosphere are becoming ever greater with biotechnical
advances. For instance, salmon on fish farms, genetically modified to grow faster
and larger, could outcompete natural varieties if they escaped into the wild. Worst
of all, new diseases, unwittingly released, could devastate species. Above all, this
impending diminution of nature's riche connotes a failure of our stewardship of the
planet.
But the yearning for an unspoilt "natural" world is naive. The environment
many of us cherish and feel most attuned to—in my case the English countryside—
is an artificial creation, the outcome of centuries of intensive cultivation, enriched
by many
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seems destined to continue rising until 2050, by which time it will have
reached eight billion. This projection follows from the fact that the present age
distribution in developing countries is sharply skewed towards the young, so an
increase would continue even if these people had less than the replacement level of
children. This increase, combined with the trend towards urbanisation, will lead to
at least twenty "megacities" with populations exceeding twenty million.
But the surprisingly rapid fall in fertility, stemming from the empowerment
of women, has led the UN to reduce its projections for the second half of this
century. The best current guess is that after 2050 the population will start to drop,
perhaps falling back to its present-day value by the end of the century, unless
medical advances boost life expectancy to the extent that some futurologists
predict. The "over-fifties" will dominate in Europe and North America, even
without any novel techniques for extending life span. This trend may be masked,
particularly in the US, by immigration from the developing world, where
stabilisation and consequent decline (if it ever happens) will be delayed.
Of course, the extrapolation is based on assumptions about social trends. If
European countries became genuinely anxious about falling population,
governments could readily introduce measures to stimulate fertility. Contrariwise,
epidemics spreading within megacities could cause catastrophic declines of the kind
already projected for parts of Africa, and by 2050 such predictions could be
radically changed by technical advances in robotics and medicine as drastic as those
that techno-enthusi-asts envisage.
The most benign outcome, if we could indeed survive the next century
without catastrophic reversals, would be a world with a population lower than at
present (and far below its projected peak in around 2050).
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A new hazard that must be folded into these projections, and perhaps a
portent of others, is the AIDS epidemic. This didn't catch hold in the human
population until the 1980s, and it still hasn't reached its peak. Almost ten percent of
South Africa's forty-two million people are believed to be HIV positive: AIDS is
predicted to cause seven million deaths by 2010 in that country alone, wiping out
much of the most productive age group, cutting the life expectancy of both men and
women by as much as twenty years, and leaving millions of traumatised orphans
among the younger generation. The burgeoning AIDS pandemic will devastate
Africa; millions of cases are projected in Russia; the total numbers infected are
rising fast in China and India, where fatalities from AIDS may exceed African
levels within a decade.
Can we expect other calamitous "natural" plagues? Some experts have been
reassuring about our likely susceptibility. Paul W. Ewald, for instance, notes that
global migrations, and the consequent mixing of people over the last century, have
exposed everyone to pathogens from all parts of the world, but there has been only
one devastating pandemic: HIV-AIDS. The other naturally occurring viruses, like
ebola, are not durable enough to generate a runaway epidemic. But Ewald's mildly
upbeat appraisal leaves aside the risk of some epidemic ' triggered by bioerror or
bioterror, rather than by nature.
Earth's Inconstant Climate
Climatic change has, like extinction of species, characterised Earth
throughout its history. But it has, like the extinction rate, been disquietingly
speeded up by human actions.
The climate has undergone natural changes on every time scale, from
decades to hundreds of millions of years. Even
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within the era of recorded history the regional climate has varied markedly.
It was warmer in Northern Europe a thousand years ago: there were agricultural
settlements in Greenland where animals grazed on land that is now ice-covered; and
vineyards flourished in England. But there have been prolonged cold periods too.
The warm spell seems to have ended by the fifteenth century, to be succeeded by a
"little ice age" that continued until the end of the eighteenth century. There are
regular records of the ice on the Thames getting so thick during much of that period
that fires were lit on it; glaciers in the Alps advanced. The "little ice age" may offer
important clues to a question that has been perennially controversial: whether vari-
ability of the Sun could trigger alterations in the climate. During this cold spell, the
Sun seemed to have been behaving slightly erratically: in the second half of the
seventeenth century and the first years of the eighteenth there was a mysterious sev-
enty-year period, (now known as the Maunder minimum, after the scientist who
first noticed it) in which there were hardly any sunspots at all. The activity on the
Sun's turbulent surface— flares, sunspots and so forth—normally rises to a peak
and then drops again, repeating this cycle somewhat unsteadily, but roughly every
eleven or twelve years. Claims that this cycle affects the climate date back more
than two hundred years, but are still controversial. (It has even been alleged that the
economic cycle "tracks" solar activity.) There are also claims that the length of a
particular cycle—whether it is closer to eleven years or twelve years—affects the
average temperature.
Nobody really understands how sunspots and flaring activity (or their
absence) could affect the climate to this extent. Sunspots are linked to the magnetic
behaviour of the Sun, and to the flares that generate fast-moving particles that hit
Earth. These particles themselves, however, carry only a tiny fraction of the Sun's
energy, but we should be open-minded about the possibility that some "amplifier"
in the upper atmosphere might enable them to trigger substantial changes in cloud
cover. Scientists have often been caught out in the past, rejecting evidence staring
them in the face because they couldn't at the time think of how to explain it. (A
spectacular instance of this is continental drift. The coastline of Europe and Africa
seems to fit that of the Americas, like a jigsaw puzzle, as though these landmasses
had once been joined and had drifted apart. Until the 1960s, nobody understood
how the continents could move, and some leading geophysicists denied the
evidence of their own eyes rather than accept that continental motion might be
induced by some mechanism that they hadn't been astute enough to think of.)
There are other environmental effects on climate, such as major volcanic
eruptions. The 1815 eruption of the Tambora volcano in Indonesia propelled about
one hundred cubic kilometres of dust into the stratosphere, along with gases that
combined with water vapour to create an aerosol of sulphuric acid droplets.
Exceptionally cold weather the following year, both in Europe and in New England,
led to 1816 being termed "the year without a summer." (Mary Shelley wrote her
gothic fantasy Frankenstein—the first modern science fiction novel—during that
year's unseasonable weather, while holed up in Byron's rented villa on the shores of
Lake Geneva.)
One human-induced atmospheric change that was completely unpredicted
was the emergence of the ozone hole over the Antarctic caused by chemical
reactions of chloroihiorocarbons (CFCs) in the stratosphere that depleted/the ozone
layer. International agreement to phase out the culprit CFCs, used in aerosol cans
and as a coolant in domestic refrigerators, has ameliorated this problem: the ozone
hole is now filling in. But we were actually lucky that this problem was so readily
remedied. Paul Crutzen, one of the chemists who elucidated how
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CFCs actually acted in the upper atmosphere, has pointed out that it was a
technological accident and quirk of chemistry that the commercial coolant adopted
in the 1930s was based on chlorine. Had bromine been used instead, the
atmospheric effects would have been more drastic and longer-lasting.
Greenhouse warming
In contrast to ozone depletion, global warming due to the so-called
"greenhouse effect" is an environmental problem for which there is no quick fix.
This effect comes about because the atmosphere is more transparent to incoming
sunlight than to the infrared "heat radiation" that is emitted by the Earth; the heat is
therefore trapped, rather as in a greenhouse. Carbon dioxide is one of the
"greenhouse gases" (water vapour and methane being others) that trap the heat.
Atmospheric carbon dioxide is already fifty percent above its pre-industrial level,
because of the increasing consumption of fossil fuels. There is a consensus that this
accumulation will make the world hotter in the twenty-first century than it would
otherwise be, but exactly how much hotter is still unclear.The main temperature rise
is likely to be between two and five degrees. Few venture more precise predictions;
many warn that even more extreme scenarios cannot be ruled out. Even if the rise
were just two degrees, a very conservative estimate, there could be serious localised
consequences (e.g., more storms and other extreme weather).
There is nothing optimal about the Earth's present climate: it is simply
something to which human civilization has accommodated over the centuries, as
have the animals and plants (both natural and agricultural) with which we share the
ter-rain.The reason that the impending global warming could be threateningly
disruptive is that it will happen much more rapidly than the naturally occurring
changes in the historical past; too fast for human populations, land-use patterns, and
natural vegetation to adjust to. Global warming may induce a rise in sea level, an
increase in severe weather, and a spread of mosquito-borne diseases to higher
latitudes. On the bright side (from our human perspective) the climate in Canada
and Siberia will become more temperate.
Steady global warming at the "conservative best guess" rate would impose
costs in agricultural adjustments, sea defenses and other areas, and aggravate
droughts in some regions. Concerted action by governments to reduce global
warming is certainly worthwhile. It would be an exaggeration, however, to regard a
temperature rise of two or three degrees as in itself a global catastrophe. It would be
a setback to economic advance, and an impoverishment of many nations. Famines
within a country most often arise from maldistribution of wealth, rather than an
overall shortage of food, and can be ameliorated by government action. Likewise,
the consequences of climate change could be softened, and distributed more
equitably, by international action.
The apparent slow-down in population growth is of course good news for
global warming scenarios: fewer people mean less emission. But there is so much
inertia in the atmospheric and ocean systems that, whatever happens, a rise of at
least two degrees in mean temperature by 2100 seems likely. Any projections
beyond that time obviously depend on how large the population would be, and how
people live and work. Even more, the long-range prognosis will depend on whether
fossil fuels are replaced by alternative sources of energy. Optimists hope that this
will happen as a matter of course. The anti-gloom environmental propagandist
Bjorn Lomberg quotes a Saudi-Arabian oil minister's dictum that "the oil age will
end, but not for lack of oil, just as the stone age ended, but not for lack of
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stones." But most experts believe government-imposed ceilings on carbon
dioxide emission are worthwhile not only for their direct impact, but as a stimulus
to development of more efficient renewable energy sources.
What Are the "Worst Cases?"
For the bulk of the world's population, the twentieth century ideological
stances of East-West relations that motivated the nuclear confrontation were an
irrelevant distraction from the immediate problems of poverty and environmental
hazard. To the age-old "threats without enemies" (earthquake, storm and drought)
must now be added the man-made threats to the biosphere and the oceans. The
Earth's biosphere has of course changed ceaselessly over its history. But the current
changes— pollution, loss of biodiversity, global warming, etc.—are unprecedented
in their speed.
The problems of environmental degradation will become far more
threatening than they even are today. The ecosystem may not be able to adjust to
them. Even if global warming occurs at the slower end of the likely range, its
consequences—competition for water supplies, for example, and large-scale migra-
tions—could engender tensions that trigger international and regional conflicts,
especially if these are further fuelled by continuing population growth. Moreover,
such conflict could be aggravated, perhaps catastrophically, by the increasingly
effective disruptive techniques with which novel technology is empowering even
small groups.
The interaction of atmosphere and oceans is so complex and uncertain that
we can't discount the risk of something much, more drastic than the "best guess"
rate of global warming. The rise by 2100 could even exceed five degrees. Even
worse, the temperature change may not be just in direct (or "linear") proportion to
the rise in the carbon dioxide concentration. When some threshold level is reached,
there could be a sudden and drastic "flip" to a new pattern of wind and ocean
circulation.
The Gulf Stream is part of a so-called "conveyor-belt" flow pattern whereby
warm water flows north-eastward towards Europe near the surface, and returns,
having cooled, at greater depths.The melting of Greenland's ice would release a
huge volume of fresh water, which would mix with the salt water, diluting it and
rendering it so buoyant that it would not sink even after it had cooled. This injection
of fresh water could thereby quench the "thermohaline" circulation pattern
(controlled by the ocean's salinity and temperature) that is crucial for maintaining
the temperate climate of northern Europe. If the Gulf Stream were truncated or
reversed, Britain and neighboring countries could be plunged into near-arctic
winters, like those that currently prevail in similar latitudes in Canada and Siberia.
We know that changes of this kind happened in the past because cores drilled
through the ice sheets of Greenland and the Antarctic provide a kind of fossil record
of temperatures: each year fresh ice freezes on top and squeezes down the earlier
layers. Many times during the last hundred thousand years there seem to have been
drastic cooling-offs within decades or less. The climate has actually been unusually
stable during the last eight thousand years. The worry is that human-induced global
warming may render the next "flip" much more imminent.
"Flipping" of the Gulf Stream would be a disaster for Western Europe, even
though it might have a countervailing "upside" elsewhere. Another scenario
(admittedly unlikely)would be a so called "runaway greenhouse effect" where
rising temperatures cause a positive feedback that releases still more greenhouse
gas. Earth would need to be already substantially
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hotter than it actually is to be at any risk from runaway evaporation of water
from the oceans (water vapour being a greenhouse gas). But we cannot so firmly
exclude a runaway due to the release of huge amounts of methane (at least twenty
times as efficient as carbon dioxide as a greenhouse gas) trapped in the soil. Such a
runaway would be a global disaster.
If we could be absolutely sure that nothing more drastic than "linear"
changes in the climate could occur, it would be reas-suring. The small chance of
something really catastrophic is more worrying than the greater chance of less
extreme events. Not even the most drastic conceivable climatic shifts could directly
destroy all humanity, but the worst of them, accompanied by transitions to far more
variable and extreme weather patterns, could negate decades of economic and
social advance.
Even a one-percent chance that human-induced atmospheric changes could
trigger an extreme and sudden climatic transition—and a meteorologist would need
to be very confident indeed to set the odds as low as that—is a disquieting enough
prospect to justify precautionary measures more drastic than those already proposed
by the Kyoto agreements (which require industrialized countries to reduce their
carbon dioxide emissions to 1990 levels by 2012). Such a threat would be a
hundred times larger than the baseline risk of environmental catastrophe that the
Earth is exposed to, irrespective of human actions, from asteroid impacts and
extreme volcanic events.
I conclude this chapter with a sober assessment from Charles, Prince of
Wales, whose views are seldom quoted approvingly by scientists: "The strategic
threats posed by global environment and development problems are the most
complex, interwoven and potentially devastating of all the challenges to our
security. Scientists ... do not fully understand the consequences of our many-faceted
assault on the interwoven fabric of atmosphere, water, land and life in all its
biological diversity. Things could turn out to be worse than the current scientific
best guess. In military affairs, policy has long been based on the dictum that we
should be prepared for the worst case. Why should it be so different when the
security is that of the planet and our long-term future?"
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9. EXTREME RISKS
A Pascalian Wager
Some experiments could conceivably threaten the entire Earth. How
close to zero should the claimed risk be before such experiments are
sanctioned?
THE MATHEMATICIAN AND MYSTIC Blaise Pascal offered a famous
argument for devout behaviour: even if you thought it exceedingly unlikely that a
vengeful God existed, you would be prudent and rational to behave as though He
did, because it is worth paying the (finite) price of forgoing illicit pleasures in this
life as an "insurance premium" to guard against even the smallest probability of
something infinitely horrible—eternal Hellfire—in the afterlife. This argument
seems to carry little resonance today, even among proclaimed believers.
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Pascal's celebrated "wager" is an extreme version of the "precautionary
principle." This line of reasoning is widely invoked in health and environmental
policy. For example, the long-term consequences of genetically modified plants and
animals for human health, and for ecological balance, are manifestly uncertain: a
calamitous outcome may seem improbable, but we cannot say that it is impossible.
Proponents of the precautionary principle urge that we should proceed cautiously,
and that the onus should be on the advocates of genetic modification to convince
the rest of us that such fears are ungrounded—or, at the very least, that the risks are
small enough to be outweighed by some specific and substantial benefits. An
analogous argument is that we should forgo the benefits of extravagant energy
consumption, and thereby reduce the deleterious consequences of global
warming—especially the small risk that its consequences could be far more serious
than the "best guess" suggests.
The obverse of technology's immense prospects is an escalating variety of
potential disasters, not just from malevolent in- tent but from innocent inadvertence
as well. We can conceive of events—albeit unlikely ones—that could cause
worldwide epidemics of fatal diseases to which there is no antidote, or change
society irreversibly. And robotics and nanotechnology could in the long term be
even more threatening.
However, it is not inconceivable that physics could be dangerous too. Some
experiments are designed to generate condi-. tions more extreme than ever occur
naturally. Nobody then knows exactly what will happen. Indeed, there would be no
point in doing any experiments if their outcomes could be fully predicted in
advance. Some theorists have conjectured that certain types of experiment could
conceivably unleash a runaway process that destroyed not just us but Earth itself.
Such an event seems far less likely than the human-induced bio- or
nanocatastrophes that could befall us during this century—less likely, indeed, than
a massive asteroid impact. But if such a disaster occurred, it would by any
reckoning be worse than "merely" destroying civilisation, or even destroying all
human life. It raises the issue of how we quantify relative degrees of awfulness, and
what precautions should be taken (by whom) against occurrences that might seem
to have an infinitesimal probability, but which could lead to an "almost infinitely
bad" calamity. Should we forgo some kinds of experiments, for the same reason
that Pascal recommended prudent behaviour?
Risking the Earth
Promethean concerns of this kind go back to the atomic bomb project during
the Second World War. Could we be absolutely sure, some then wondered, that a
nuclear explosion wouldn't ignite all the world's atmosphere or oceans? Edward
Teller contemplated this scenario as early as 1942, and Hans Bethe made a quick
calculation that seemed reassuring. Before the 1945 "Trinity" test of the first atomic
bomb in New Mexico, Teller and two colleagues addressed the question in a Los
Alamos report. The authors focused on a possible runaway reaction of atmospheric
nitrogen, and wrote that "the only disquieting feature is that the 'safety factor'
decreases rapidly with initial temperature." This inference led to renewed concern
in the 1950s, because hydrogen (fusion) bombs indeed generate even higher
temperatures; another physicist, Gregory Briet, revisited the problem before the
first H-bomb test. It is now clear that the actual "safety factor" was very large
indeed. One nonetheless wonders how small the contemporary estimates of that
factor would have needed to be before those in charge would have felt it prudent to
abandon the H-bomb tests.
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We now know for certain that a single nuclear weapon, devastating though it
is, cannot trigger a nuclear chain reaction that would utterly destroy Earth or its
atmosphere. (The entire arsenals of the US and the Russia, were they to be
unleashed, could nevertheless have an effect as bad as any natural disaster that
could be expected in the next hundred thousand years.) But some physics
experiments carried out for reasons of pure scientific inquiry could conceivably—or
so some have claimed—pose a global, even cosmic, threat. These experiments offer
an interesting "case study" of who should decide (and how) whether to sanction an
experiment with a catastrophic "downside" that is very improbable but not quite in-
conceivable, especially when the leading experts may not have enough confidence
in their theories to offer the compelling level of reassurance that the public might
properly expect.
Most physicists (and I would count myself among them) would rate these
threats as very, very improbable. But it is important to make clear what such a
rating actually means. There are two distinct meanings of probability. The first,
leading to a firm and objective estimate, applies when the underlying mechanism is
well understood, or when the event being studied has happened many times in the
past. For instance, it is easy to work out that when an unbiased coin is tossed ten
times the chance of getting ten heads is a bit less than one in a thousand; and the
chance of catching measles during an epidemic may also be quantified, because
even though we may not understand all the biological details of virus transmission,
we have data on many earlier epidemics. But there is a second kind of probability
that reflects no more than an informed guess, and may alter as we learn more. (The
assessments that different experts give of, for instance, the consequences of global
warming are "subjective likelihood" estimates of a similar kind.) In a criminal
investigation, the police may say that it "seems very probable" or "is highly
improbable" that a body is buried in a particular place. But this reflects just the
betting odds they would offer in the light of the available evidence. Further digging
will reveal that the body either is or isn't there, and the probability is thereafter
either one or zero. When physicists contemplate an event that has never happened
before, or a process that is poorly understood, any assessment they can offer
resemble this second kind of probability: it is an informed guess, buttressed (often
very strongly) by well-established theories but nonetheless open to revision in the
light of new evidence or insight.
Our "Final" Experiment?
Physicists aim to understand the particles that the world is made of, and the
forces that govern those particles. They are eager to probe the most extreme
energies, pressures, and temperatures; for this purpose they build huge and
elaborate machines: particle accelerators. The optimum way to produce an intense
concentration of energy is to accelerate atoms to enormous speeds, close to that of
light, and crash them together. It is best of all to use very heavy atoms. A gold
atom, for instance, has nearly two hundred times the mass of a hydrogen atom. Its
nucleus contains 79 protons and 118 neutrons. A lead nucleus is heavier still,
containing 82 protons and 125 neutrons. When two such atoms are crashed
together, their constituent protons and neutrons implode to a density and pressure
far higher than what they were when they were packed into a normal gold or lead
nucleus. They may then break up into still smaller particles. According to theory,
each proton and neutron consists of three quarks, so the resultant "splat" releases
over a thousand quarks. These ultra-fast atomic collisions actually replicate, in120
Our Final Hour
microcosm, those that prevailed in the first microsecond after the "big bang,"
when all the matter in the universe was squeezed into a so-called quark-gluon
plasma.
Some physicists raise the possibility that these experiments might do
something far worse than smashing a few atoms, like destroying our Earth, or even
our entire universe. Such an event is the theme of Greg Benford's novel COSM,
where an experiment at Brookhaven laboratory devastates the accelerator and
creates a new "microuniverse" (which remains, comfortingly, encased within a
sphere small enough to be carried around by its graduate-student creator).
An experiment that generates an unprecedented concentration of energy
could—conceivably, but highly implausibly— trigger three quite different disaster
scenarios.
Perhaps a black hole could form, and then suck in everything around it.
According to Einstein's theory of relativity, the energy needed to make even the
smallest black hole would far exceed what these collisions could generate. Some
new theories, however, invoke extra spatial dimensions beyond our usual three; a
consequence would be to strengthen gravity's grip, rendering it less difficult than
we previously thought for a small object to implode into a black hole. But the same
theories suggest that these holes would still be innocuous, because they would
erode away almost instantly, rather than tugging in more stuff from their
surroundings.
The second frightening possibility is that the quarks might reassemble
themselves into a very compressed object called a strangelet. That in itself would be
harmless: the strangelet would still be far smaller than a single atom. However, the
danger is that a strangelet could, by contagion, convert anything else it encountered
into a strange new form of matter. In Kurt Vonnegut's novel Cat's Cradle a
Pentagon scientist produces a new form of ice, "ice nine," that is solid at ordinary
temperatures; when it escapes from the laboratory it "infects" natural water, and
even the oceans solidify. Likewise, a hypothetical strangelet disaster could
transform the entire planet Earth into an inert hyperdense sphere about one hundred
metres across.
The third risk from these collision experiments is still more exotic, and
potentially the most disastrous of all: a catastrophe that engulfs space itself. Empty
space—what physicists call "the vacuum"—is more than just nothingness. It is the
arena for everything that happens: it has, latent in it, all the forces and particles that
govern our physical world. Some physicists suspect that space can exist in different
"phases," rather as water can exist in three forms: ice, liquid, and steam. Moreover,
the present vacuum could be fragile and unstable. The analogy here is with water
that is "supercooled." Water can cool below its normal freezing point if it is very
pure and still; however, it takes only a small localised disturbance—for instance, a
speck of dust falling into it—to trigger supercooled water's conversion into ice.
Likewise, some have speculated that the concentrated energy created when particles
crash together could trigger a "phase transition" that would rip the fabric of space
itself. The boundary of the new-style vacuum would spread like an expanding
bubble. In that bubble atoms could not exist: it would be "curtains" for us, for
Earth, and indeed for the wider cosmos; eventually, the entire galaxy, and beyond,
would be engulfed. And we would never see this disaster coming. The "bubble" of
new vacuum advances as fast as light, and so no signal could forewarn us of our
fate. This would be a cosmic calamity, not just a terrestrial one.
These scenarios may seem bizarre, but physicists discuss them with a straight
face. The most favoured theories are reassuring: they imply that the risk is zero. But
we cannot be one hundred percent sure what might actually happen. Physicists can
dream up alternative theories (and even write down equa- 122
tions) that are consistent with everything we know, and therefore cannot be
absolutely ruled out, but that would allow one or other of these catastrophes to
happen. These alternative theories may not be frontrunners, but are they all so
incredible that we needn't worry?
Back in 1983, physicists were already becoming interested in high-energy
experiments of this kind. While visiting the Institute for Advanced Study in
Princeton, I discussed these issues with a Dutch colleague, Piet Hut, who was also
visiting Princeton and subsequently became a professor there. (The academic style
of this institute, where Freeman Dyson has long been a professor, encourages "out
of the box" thinking and speculations.) Hut and I realised that one way of checking
whether an experiment is safe would be to see whether nature has already done it
for us. It turned out that collisions similar to those being planned by the 1983
experimenters were a common occurrence in the universe. The entire cosmos is
pervaded by particles known as cosmic rays that hurtle through space at almost the
speed of light; these particles routinely crash into other atomic nuclei in space, with
even greater violence than could be achieved in any currently feasible experiment.
Hut and I concluded that empty space cannot be so fragile that it can be ripped apart
by anything that physicists could do in their accelerator experiments. If it were,
then the universe would not have lasted long enough for us to be here at all.
However, if these accelerators became a hundred times more powerful— something
that financial constraints still preclude, but which may be affordable if clever new
designs are developed—then these concerns would revive, unless in the meantime
our understanding has advanced enough to allow us to make firmer and more
reassuring predictions from theory alone.
The old fears resurfaced more recently when plans were announced, both at
the Brookhaven National Laboratory in the US and at the CERN laboratory in
Geneva, to crash atoms together even more forcefully than had been done before.
The director of the Brookhaven Laboratory at the time, John Mar-burger (now
President Bush's scientific advisor), asked a group of experts to look into the issue.
They did a calculation along the lines of the one that Hut and I had given, and
offered reassurance that there was no threat of a cosmic Doomsday triggered by
tearing the fabric of space.
But these physicists could not be quite so reassuring about the risk from
strangelets. Collisions with the same energy certainly occur in the cosmos, but
under conditions that differ in relevant respects from those of the planned terrestrial
experiments; these differences could alter the likelihood of a runaway process.
Most of the "natural" cosmic collisions happen in interstellar space, in an
environment so rarefied that even if they produced a strangelet, it would be unlikely
to encounter a third nucleus, so there would be no chance of a runaway process.
Collisions with Earth also differ in an essential way from those in accelerators,
because incoming nuclei are stopped in the atmosphere, which does not contain
heavy atoms like lead and gold.
Some fast-moving nuclei, however, impact directly on the Moon's solid
surface, which does contain such atoms. Such impacts have occurred over its entire
history. The Moon is nonetheless still there, and the authors of the Brookhaven re-
port proffered this indisputable fact as reassurance that the proposed experiment
couldn't wipe us out. But even these impacts differ in one possibly important way
from those that would occur in the Brookhaven accelerator. When a fast particle
crashes onto the Moon's surface, it hits a nucleus that is almost at rest, and gives it a
"kick" or recoil. The resultant strangelets, produced as debris in the collision, would
share this recoil motion, and therefore be sent hurtling through the lunar material.
In contrast, the accelerator experiments involve symmetrical collisions, where two
particles approach each
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other "head on." There is then no recoil: the strangelets have no net motion
and therefore might stand more chance of grabbing ambient material.
Since the experiment would generate conditions that have never happened
naturally, the only reassurance came from two theoretical arguments. First, even if
strangelets could exist, theorists thought it unlikely that they would form in these
violent collisions: it seemed more likely that the debris would disperse in the
aftermath of the collision, rather than reassembling into a single lump. Second, if
strangelets form, theorists would expect them to have a positive electric charge. On
the other hand, to trigger runaway growth the strangelets would have to be a
negatively charged (so that they would attract, rather than re-pel, positively charged
atomic nuclei in their surroundings).
The best theoretical guesses are therefore reassuring. Sheldon Glashow, a
theorist, and Richard Wilson, an expert on energy and environmental issues,
succinctly summarised the situation like this: "If strangelets exist (which is
conceivable), and if they form reasonably stable lumps (which is unlikely), and if
they are negatively charged (although the theory strongly favours positive charges),
and if tiny strangelets can be created at the [Brookhaven] Relativistic Heavy Ion
Collider (which is exceedingly unlikely), then there might just be a problem. A
new-born strangelet could engulf atomic nuclei, growing relentlessly and ultimately
consuming the entire Earth. The word 'unlikely,' however many times it is repeated,
just isn't enough to assuage our fears of this total disaster."
What Risks Are Acceptable?
The accelerator experiments didn't give me any sleepless nights. Indeed, I
don't know of any physicist who betrayed the
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slightest anxiety about them. However, these attitudes are little more than
subjective assessments, based on some knowledge of the relevant science. The
theoretical arguments depend on probabilities rather than certainties, as Glashow
and Wilson spell out clearly. There is no evidence that exactly the same conditions
have ever occurred naturally. We cannot be absolutely sure that strangelets couldn't
lead to a runaway disaster. The Brookhaven report (and a parallel effort by
scientists from the biggest European accelerator, CERN, in Geneva) were presented
as reassuring. However, even if one accepted their reasoning completely, the level
of confidence they offered hardly seemed enough. They estimated that if the
experiment were run for ten years, the risk of a catastrophe was no more than one in
fifty million. These might seem impressive odds: a chance of disaster smaller than
the chance of winning the UK's national lottery with a single ticket, which is about
one in fourteen million. However, if the downside is destruction of the world's
population, and the benefit is only to "pure" science, this isn't good enough. The
natural way to measure the gravity of a threat is to multiply its probability by the
number of people at risk, to calculate the "expected number" of deaths. The entire
world's population would be at risk, so the experts were telling us that the expected
number of human deaths (in that technical sense of "expected") could be as high as
120 (the number obtained by taking the world's population to be six billion and
dividing by fifty million).
Obviously, nobody would argue in favour of doing a physics experiment
knowing that its "fallout" could kill up to 120 people. This is not, of course, quite
what we were told in this case: we were told instead that there could be up to one
chance in fifty million of killing six billion people. Is this prospect any more
acceptable? Most of us would, I think, still be uneasy. We are more tolerant of risks
that we expose ourselves to voluntarily, -
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or if we see some compensating benefit. Neither of these conditions pertains
here (except for those physicists who are actually interested in what might be learnt
from the experiment). My Cambridge colleague Adrian Kent has emphasised a sec-
ond factor: the finality and completeness of the extinction that this scenario would
entail. It would deprive us of an expectation—important to most of us—that some
biological or cultural legacy will survive our deaths; it would dash the hope that our
lives and our works may be part of some continuing progress. It would, worse still,
foreclose the existence of a (perhaps far larger) total number of people in all future
generations. Wiping out all the world's people (and indeed destroying not just hu-
mans but the entire biosphere) could therefore be deemed far more than six billion
times worse than the death of one person. So perhaps we should set an even more
stringent threshold on the possible risk before sanctioning such experiments.
Philosophers have long debated how to balance the rights and interests of
"possible people," who might have some future existence, against those of people
who actually exist. For some, like Schopenhauer, the painless elimination of the
world would not rate as an evil at all. But most would resonate more with Jonathan
Schell's response: "While it is true that extinction cannot be felt by those whose fate
it is—the unborn, who would stay unborn—the same cannot be said, of course, for
extinction's alternative, survival. If we shut the unborn out of life, they will never
have the chance to lament their fate, but if we let them into life they will have
abundant opportunity to be glad that they were born instead of having been
prenatally sev- ered from existence by us. What we must desire first of all is that
people be born, for their own sakes, and not for any other reason. Everything else—
our wish to serve the future generations by preparing a decent world for them to
live in, and our wish to lead a decent life ourselves in a common world made
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secure by the safety of the future generations—flows from this commitment.
Life comes first, the rest is secondary."
Who Should Decide?
No decision to go ahead with an experiment with a conceivable "Doomsday
downside" should be made unless the general public (or a representative group of
them) is satisfied that the risk is below what they collectively regard as an
acceptable threshold. The theorists in this episode seemed to have aimed to reassure
the public about a concern that they considered unreasonable, rather than to make
an objective analysis. The public is entitled to more safeguards than that. It isn't
good enough to make a slapdash estimate of even the tiniest risk of destroying the
world.
Francesco Calogero is one of the few who have addressed this issue
thoughtfully. He is not only a physicist, but also a long-time activist for arms
control, and a former general secretary of the Pugwash conferences. He expresses
his concerns like this: "I am somewhat disturbed by what I perceive to be the lack
of candour in discussing these matters. . . Many, indeed most [of those with whom I
have had private discussion and exchanged messages] seem more concerned with
the public relations impact of what they, or others, say or write, than in making sure
that the facts are presented with complete scientific objectivity."
How should society guard against being unknowingly exposed to a not-quite-
zero risk of an event with an almost infinite downside? Calogero suggests that no
experiment that could conceivably carry such risks should be approved without a
prior exercise, of a kind familiar from risk analyses in other contexts, involving a
"Red Team" of experts (which would not
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include any of the group actually proposing the experiment) that would play
devil's advocate, trying to think of the worst that might happen, and a "Blue Team"
that would try to think of antidotes or counter-arguments.
When the purpose is to probe conditions where the physics is "extreme" and
very poorly known, it is hard to rule out anything completely. Can we ever be sure
enough of our reasoning to offer reassurance with the confidence level of a million,
a billion, or even a trillion to one? Theoretical arguments can seldom offer adequate
comfort at this level: they can never be firmer than the assumptions on which they
are based, and only recklessly overconfident theorists would stake odds of a billion
to one on the validity of their assumptions.
Even if a believable number could be assigned to the probability of a
catastrophic outcome, the question remains: How low would the alleged risk have
to be before we would give our informed consent to these experiments? There is no
specific countervailing benefit to the rest of us, so the level would surely be lower
than the experimenters might willingly accept ... on their own behalf. (It would
also be far lower than the risk of nuclear devastation that citizens might have
accepted during the Cold War, based on their personal assessment of what was at
stake.) Some would argue that one chance in fifty million was low enough, because
that is below the chance that within the next year an asteroid large enough to cause
global devastation will strike Earth. (This is like arguing that the extra carcinogenic
effect of artificial radiation is acceptable if it does not do more than double the risk
from natural radiation.) But even this limit doesn't seem stringent enough. We may
become resigned to a natural risk (like asteroids or natural pollutants) that we
cannot do much about, but that doesn't mean that we should acquiesce in an extra
avoidable risk of the same magnitude. Indeed, efforts are made to reduce risks far
below that level whenever we can. That is why, for example, it is worth some effort
to ameliorate the risk of asteroid impact.
UK government guidelines on radiation hazards deem it unacceptable that
even the limited group of workers in a nuclear power station should risk more than
one chance in one hundred thousand per year of dying through the effects of radia-
tion exposure. If this very risk-averse criterion were applied to the accelerator
experiment, taking the world's population as being at risk but accepting an equally
stringent maximum number of deaths, we would require an assurance that the
chance of catastrophe was below one in a thousand trillion (10 I5). If equal weight
were attached to the lives of all potential people who might ever exist—a
philosophically controversial stance, of course—then it could even be argued that
the tolerable risk was up to a million times lower still.
The Hidden Cost of Saying No
This leads to a quandary. The most extreme precautionary policy would
prohibit any experiment that created novel artificial conditions (unless we knew
that the same conditions had already been created naturally somewhere). But this
would utterly paralyse science. Obviously, producing a new kind of material—a
new chemical, for example—shouldn't be banned: we are overwhelmingly
confident that in such a case we understand the basic principles. But once we get to
the threshold of danger, when the creation is, say, a new pathogen, then maybe we
should pause. And physics experiments at ultrahigh energies break atomic nuclei
into constituents that are not well understood, and so perhaps we should pause here,
too.
There is a penumbra of cases in which, were we to put the clock back,
caution might have been called for. For instance, 130
refrigerators in scientific laboratories routinely use liquid helium to create
temperatures within a fraction of a degree of absolute zero (-273 degrees
centigrade). Nowhere in nature—not on Earth, nor even (we believe) elsewhere in
the universe—is as cold as this: everything is warmed to nearly three degrees above
absolute zero by the weak microwaves that are a relic of the universe's hot dense
beginning, the afterglow of creation. Dr. Peter Michelson, of Stanford University,
built a detector for cosmic gravitational waves, the slight ripples in the structure of
space itself that astronomers predict should be generated by cosmic explosions.
This instrument consisted of a metal bar, weighing over a tonne, cooled close to
absolute zero in order to reduce the heat vibrations. He described this bar as "the
coldest large object in the universe, not just on Earth." This boast may have been
accurate (unless extraterrestrials had done similar experiments).
Should we really have worried when the first liquid-helium refrigerator was
turned on? I think we should have. It is true that there were no theories at the time
that pointed towards any danger. But that could have just been lack of imagination:
there are some current theories (admittedly very unlikely ones) that predict a
genuine risk, but when ultralow temperatures were first achieved, the uncertainties
were far greater, and physicists surely couldn't have confidently claimed that the
probability of catastrophe was less than one in a trillion. You might offer such
extreme odds against the possibility that the Sun won't rise tomorrow, or that a fair
die will give one hundred sixes in a row. But these cases depend on physical and
mathematical principles that are readily understood and firmly
"battle tested."
In deciding whether to sanction some new tampering with our environment,
we need to ask: Is there really a deep and firm enough understanding that we can
rule out catastrophe
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with a confidence level that reassures us? One cannot disagree with Adrian
Kent's comment: "It is obviously unsatisfactory that the question of what
constitutes an acceptable catastrophe risk should be decided, in an ad hoc way,
according to the personal risk criteria of those who happen to be consulted—those
criteria, however sincerely held and thoughtfully constructed, may be
unrepresentative of general opinion."
Procedures with no specific aim beyond achieving a better understanding of
nature and satisfying our curiosity should meet very stringent safety requirements.
But we might acquiesce in riskier decisions being taken on our behalf if there were
some compensating benefit, especially a large and urgent one. For instance,
shortening the Second World War was almost certainly in the minds of Hans Bethe
and Edward Teller when they calculated whether the first atomic bomb test would
incinerate the entire atmosphere. With so much at stake, they might properly have
gone ahead even without the ultrahigh level of reassurance that we would expect
before sanctioning a peacetime academic experiment.
The accelerator experiments highlight a dilemma that will confront us more
and more often in other sciences: who should decide (and how) whether a novel
experiment should go ahead if a disastrous outcome is conceivable but believed to
be very, very unlikely? They provide an interesting "test case" that forces us to
focus—in a far more extreme context than any biological experiment—on how to
assess asymmetric situations where the outcome will very probably be useful and
positive, but could conceivably (but very improbably) be utterly disastrous. The
Australian mousepox episode discussed earlier showed in microcosm what could
happen if, even quite unintentionally, a dangerous pathogen were created and
released. Later in the century nonbiological micromachines may be as potentially
hazardous as rogue viruses, and an extreme
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Drexler-style "grey goo scenario" may no longer seem like science fiction.
The "downside" from even the worst conceivable biological experiment
would never be as bad as for the accelerator experiment, since the entire Earth
would not be in jeopardy. But in the fields of biology and nanotechnology—in
contrast to those that use huge particle accelerators—the experiments are smaller in
scale, and so are likely to be done in far larger numbers, and in far greater variety.
We then need assurance against even one of them going disastrously wrong. If a
million separate experiments were to be conducted—a million chances of
disaster—then the tolerable risk for each would be far lower than for a "one-shot"
experiment. Quantifying these considerations into an actual number would require
an estimate of the likely benefit. Greater risks would plainly be acceptable in ex-
periments that were integral to a programme that could manifestly save millions of
lives. The risks posed by science are sometimes the necessary concomitant of
progress: if we don't accept some risk, we may forgo great benefits.
One special line of argument is used in risk assessment, with results that are
often unduly optimistic. A major accident, for instance the destruction of an airliner
or spacecraft, can occur in various different ways, each of which requires a whole
series of mishaps (for instance, the combined or successive failure of several
components). The pattern of risk can be expressed as a "fault tree"; the odds against
each are then combined, rather as one multiplies the odds when betting on a
combination of winners in horse racing (though the arithmetic is a bit more com-
plicated because there may be several different failure modes, and the mishaps may
be correlated in a way that the outcomes of separate horse races are not). Such
calculations may overlook some crucial failure modes, and thereby offer a false
sense of reassurance. The space shuttle was thought to be safe
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enough that the risk to its crew was less than one in a thousand. But the 1986
explosion happened on the twenty-fifth shuttle flight (and the tenth flight of the
Challenger launch vehicle). In retrospect, odds of one in twenty-five would have
been a better guess. Similarly, one should be cautious about the estimates given for
various kinds of mishaps to nuclear power stations, which are calculated in a
similar way.
To calibrate a tiny risk to the entire Earth, we multiply a very small
probability by a colossal number, analogous to the most extreme asteroid impact
events on the Torino scale. The probability is never quite zero because our
fundamental knowledge of basic physics is incomplete; but even if it were very
small indeed, when multiplied by a colossal number the product could still be big
enough to worry about.
When a potentially calamitous downside is conceivable—not just in
accelerator experiments, but in genetics, robotics, and nanotechnology—can
scientists provide the ultraconfident assurance that the public may demand? What
should be the guidelines for such experiments, and who should formulate them?
Above all, even if guidelines are agreed upon, how can they be enforced? As the
power of science grows, such risks will, I believe, become more varied and widely
diffused. Even if each risk is small, they could mount up to a substantial cumulative
danger.
10.THE DOOMSDAY PHILOSOPHERS
Can pure thought tell us whether humanity's years are numbered?
PHILOSOPHERS SOMETIMES ADVANCE ingenious arguments that may seem
clinching to some, but to others seem mere wordplay, or an intellectual sleight of
hand, though it is not easy to pinpoint the flaw. There is a modern philosophical
argument that humanity's future is bleak that may seem in this dubious category,
but which (with provisos) has weathered a good deal of scrutiny. The argument was
invented my friend and colleague Brandon Carter, a pioneer in the use of the so-
called anthropic principle in science, the idea that laws governing the universe must
have been rather special in order for life and complexity to have emerged. He first
presented this
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argument, to the bemusement of his academic audience, at a conference
hosted by the Royal Society in London in 1983. The idea was actually just an
afterthought in a lecture discussing the likelihood that life would evolve on planets
orbiting other stars. It led Carter to conclude that intelligent life was rare elsewhere
in the universe, and that even though the Sun would keep shining for billions of
years, life's long-term future was bleak.
This "Doomsday argument" depends on a kind of "Coperni-can principle" or
"principle of mediocrity" applied to our position in time. Ever since Copernicus, we
have denied ourselves a central location in the universe. Likewise, according to
Carter, we shouldn't assume that we are living at a special time in the history of
humanity, neither among the very first nor among the very last of our species.
Consider our place in the "roll call" of Homo sapiens. We know our place only very
roughly: most estimates suggest that the number of human beings who have
preceded us is around sixty billion, so our number in the roll call is in this range. A
consequence of this figure is that ten percent of the people who have ever lived are
alive today. At first sight this seems a remarkably high proportion, given that
mankind can be traced back through thousands of generations. But for most of
human history—the entire preagricultural era before (maybe) 8000 B.C.E.—there
were probably fewer than ten million people in the world. By Roman times, world
population was around three hundred million, and only in the nineteenth century
did it rise above a billion. The dead outnumber the living, but only by a factor of
ten.
Now consider two different scenarios for humanity's future: a "pessimistic"
one, where our species dies out within one or two centuries (or if it survives longer
than that has a much diminished population), so that the total number of humans
who will ever exist is one hundred billion; and an "optimistic" scenario, where
humanity survives for many millennia with at least the present population (or
perhaps even spreads far beyond Earth with an ever-enlarging population), so that
trillions of people are destined to be born in future. Brandon Carter argues that the
"principle of mediocrity" should lead us to bet on the "pessimistic" scenario. Our
place in the roll call (about halfway through) is then entirely unsurprising and
typical, whereas in the "optimistic" scenario, where a high population persists into
the far future, those living in the twenty-first century would be early in the roll call
of humanity.
A simple analogy brings out the essence of the argument. Suppose that you
are shown two identical urns: you are told that one contains just ten tickets,
numbered from 1 to 10, and the other contains a thousand tickets, numbered from 1
to 1000. Suppose you pick one of the urns, draw a ticket from it, and find that you
have drawn the number 6. You would then surely guess that you had, very
probably, picked from the urn containing only 10 tickets: it would be very
surprising to draw a ticket number as small as 6 from the urn containing a thousand
tickets. Indeed, if you were equally likely, a priori, to have picked either urn, a
simple probability argument then shows that having drawn the number 6, the odds
are now one hundred to one that you actually chose from the urn containing only
ten tickets.
Carter argues, along the same lines as in the case of the two urns, that our
known place in the roll call of humans (about sixty billion human beings have
preceded us) tilts the argument in favour of the hypothesis that there will be only
one hundred billion humans, and would disfavour an alternative supposition that
there would be more than one hundred trillion. So the argument suggests that the
world's population cannot continue for many generation at its present level; either it
must decline gradually, and be sustained at a far lower level than at present, or a
catastrophe will overcome our species within a few generations.
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An even simpler argument was used by Richard Gott, a professor at
Princeton University with a thirty-year record of zany but original insights on
faster-than-light travel, time machines, and the like. If we come upon some object
or phenomenon, we are unlikely to be doing so very near the beginning of its life,
nor very near its end. So it is a fair presumption that something that is already
ancient will last for a long time in the future, and something that is of recent origin
shouldn't be expected to be so durable. Gott recalls, for instance, that in 1970 he
visited the Berlin Wall (then twelve years old) and the pyramids (over four
thousand years old); his argument would have predicted (correctly) that the
pyramids would be very probably be still standing in the twenty-first century; but it
would be unsurprising if the Berlin Wall wasn't (and of course, it has gone).
Gott even showed how the argument applied to Broadway shows. He made a
list of all the plays and musicals that were running on Broadway on a particular day
(May 27, 1993) and found out how long each show had been open. On that basis,
he predicted that those that had been running longest would survive furthest into the
future. Cats had already been running for 10.6 years, and it kept going for more
than seven years more. Most of the others, which had been running less than a
month, closed within a few more weeks.
Of course, most of us could have made all Gott's predictions without using
his line of argument at all, from our familiarity with basic history, the general
robustness and durability of artefacts of different types, and so forth. We also know
about American tastes, and the economics of the theatre. The more background
information we have, the more confident can our predictions be. But even a newly
landed alien devoid of such background knowledge, who knew nothing except how
long these various phenomena had existed, could have used Gott's argument to
make some crude but correct predictions. And of course the future duration of
humanity is something about which we are as ignorant as any Martian would be
about the sociology of Broadway shows. Gott therefore argues, following Carter,
that this line of reasoning can tell us something—indeed, something far from
cheerful—about the likely longevity of our species.
Obviously humankind's future cannot be stripped down to a simple
mathematical model. Our destiny depends on multitudinous factors, above all—a
main theme of this book—on choices that we ourselves make during the present
century. The Canadian philosopher John Leslie takes the line that the Doomsday
argument nonetheless tilts the odds: it should make you less optimistic about
humanity's long-range future than you would otherwise be. If you thought, a priori,
that it was overwhelmingly probable that humanity would continue, with a high
population, for millennia, then the Doomsday argument would reduce your
confidence, though you might still end up favouring that scenario. This can be
understood by generalising the urn example. Suppose that instead of just two urns,
there were millions of urns that each contained a thousand tickets and only one that
contained just ten. Then if you pick an urn at random, you would be surprised to
draw a 6. But if there were millions of "thousand-ticket" urns, then it would be less
surprising that you had drawn an unusually low number from one of them than that
you had picked the unique urn with only ten tickets in it. Likewise, if the a priori
probability strongly favours a prolonged future for humanity, then "doom soon"
might be less likely than finding ourselves coming very early in the roll call of
humanity.
Leslie can thereby resolve another conundrum that at first sight seems to
discredit the entire line of argument. Suppose that we had a fateful decision that
would determine whether the species might soon be extinguished, or else whether it
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would survive almost indefinitely. For instance, this might be the choice of
whether to foster the first community away from Earth, which, once established,
would spawn so many others that one would be guaranteed to survive. If such a
community were indeed established and flourished, we would currently find
ourselves exceedingly early in the roll call. Does the Doomsday argument somehow
constrain us towards the choice that leads to a truncated human future? Leslie
argues that we are free to choose, but that the choice we make affects the prior
probability of the two scenarios.
Another ambiguity concerns who or what should be counted: How do we
define humanity? If the entire biosphere were to be wiped out in some global
catastrophe, then there is no doubt about when the roll call ends. But if our species
were to morph into something else, would this amount to the end of humanity? If
so, the Carter-Gott argument might be telling us something different: it could offer
support for Kurzweil, Moravec, and others who predict a "takeover" by machines
within this crucial century. Or suppose there are other beings on other worlds. Then
perhaps all intelligent beings, not just humans, should be in the "reference class."
There is then no clear way to order the roll call, and the argument collapses. (Gott
and Leslie have used similar reasoning to argue against there being other worlds
with much higher populations than ours. If there were, they claim, we should be
surprised not to be in one of them.)
When I first heard Carter's Doomsday argument, it reminded me of George
Orwell's robust comment in a different context: "You must be a real intellectual to
believe that—no ordinary person could be so foolish." But pinpointing an explicit
flaw is not a trivial exercise. It is worth doing so, however, since none of us
welcomes a new argument that humanity's days may be numbered.
11.THE END OF SCIENCE?
Future Einsteins may transcend current theories of space, time and
microworld. But the holistic sciences of life and complexity pose mysteries
that human minds may never fully grasp.
WILL SCIENCE CONTINUE TO SURGE FORWARD, bringing new insights, and
perhaps further threats as well? Or will the science of the coming century be an
anticlimax after the triumphs already achieved?
The journalist John Horgan has claimed the latter: he argues that we have
already uncovered all the really big ideas. All that remains, according to Horgan, is
to fill in the details, or else to indulge in what he terms "ironic science"—flaky, ill-
disciplined conjectures about topics that will never come within the ambit of
serious empirical study. I believe that this thesis is funda-
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mentally mistaken, and that ideas as revolutionary as any that were
discovered in the twentieth century remain to be disclosed. I prefer Isaac Asimov's
viewpoint. He likened science's frontier to a fractal—a pattern with layer upon layer
of structure, so that a tiny bit, when magnified, is a simulacrum of the whole: "No
matter how much we learn, whatever is left, however small it may seem, is just as
infinitely complex as the whole was to start with."
Twentieth-century advances in understanding atoms, life, and the cosmos
rank as humankind's greatest collective intellectual achievement. (The proviso
"collective" is crucial. Modern science is a cumulative enterprise; discoveries are
made when the time is ripe, when the key ideas are "in the air," or when some novel
technique is exploited. Scientists aren't quite as interchangeable as light bulbs, but
there are nonetheless few cases in which an individual has made much difference to
the long-run development of the subject: if "A" hadn't done the work or made the
discovery, "B" would before long have done something similar. This is the way
science normally develops. A scientist's work loses its individuality, but it lasts.
Einstein has a specially honoured place in the scientific pantheon because he was
one of the few exceptions: had he not existed, his deepest insights would have
emerged much later, perhaps by a different route and through the efforts of several
people rather than just one. But the insights would eventually have been achieved:
not even Einstein left a distinctive personal imprint to match that of the greatest
writers or composers.)
Ever since the classical Greek era when earth, air, fire, and water were
believed to be the substances of the world, scientists have sought a "unified" picture
of all the basic forces of nature, and to understand the mystery of space itself.
Cosmologists are sometimes berated for being "often in error but never in doubt."
They have indeed often embraced poorly grounded
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speculations with irrational fervour, and been led by wishful thinking to read
too much into vague and tentative evidence. But even the more cautious among us
are confident that we have now grasped at least the outlines of our entire cosmos,
and learnt what it is made of. We can trace the evolutionary story back before our
solar system formed—indeed, back to an epoch long before there were any stars,
when everything sprouted from an intensely hot "genesis event," the so-called big
bang, about fourteen billion years ago. The first microsecond is shrouded in
mystery, but everything that happened since then—the emergence of our complex
cosmos from simple beginnings—is the outcome of laws that we can understand,
even though the details still elude us. Just as geophysi-cists have come to
understand the processes that made the oceans and sculpted the continents, so
astrophysicists can understand our Sun and its planets, and indeed the other planets
that may orbit distant stars.
In earlier centuries, navigators mapped the outlines of the continents and
took the measure of Earth. Within just the last few years our map of the cosmos, in
time and in space, has likewise firmed up. A challenge for the twenty-first century
is to refine our present picture, filling in ever more detail, just as generations of
surveyors did for Earth, and especially to probe the mysterious domains where
earlier cartographers wrote "here be dragons."
Shifting Paradigms
The term "paradigm" was popularised by Thomas Kuhn in his classic book
The Structure of Scientific Revolutions. A paradigm is not just a new idea (if it
were, most scientists could claim to have shifted a few): a paradigm shift denotes
an intellectual
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upheaval that reveals new insights and transforms our scientific perspective.
The greatest paradigm shift of the twentieth century was the quantum theory. This
theory tell us, completely counter to all intuition, that on the atomic scale nature is
intrinsically "fuzzy." Nonetheless, atoms behave in precise mathematical ways
when they emit and absorb light, or link together to make molecules. A hundred
years ago, the very existence of atoms was controversial; but quantum theory now
accounts for almost every detail of how atoms behave. As Stephen Hawking points
out, "It is a tribute to how far we have come in theoretical physics that it now takes
enormous machines and a great deal of money to perform an experiment [on
subatomic particles] whose result we cannot predict."
Quantum theory is vindicated every time you take a digital photograph, surf
the Internet, or use any gadget—a CD player, or a supermarket bar code—that
involves a laser. Even now some of its astonishing implications are just dawning on
us. It may allow computers to be designed on entirely new principles, that could
outperform any "classical" computer, however long Moore's law continues.
Another new paradigm of twentieth-century science—another astonishing
intellectual leap—is largely the creation of one man, Albert Einstein: he deepened
our understanding of space, time, and gravity, giving us a theory, general relativity,
that governs the motions of planets, stars, and the expanding universe itself. This
theory is now confirmed by very precise radar tracking of planets and spacecraft,
and by astronomical studies of neutron stars and black holes—objects where
gravity is so strong that space and time are grossly distorted. Einstein's theory
might have seemed arcane, but it is vindicated every time a truck or plane fixes its
position via the global positioning satellite (GPS) system.
Linking the Very Large and the Very Small
But Einstein's theory is inherently incomplete: it treats space and time as a
smooth continuum. If we chop a piece of metal (or indeed, any material at all) into
smaller and smaller pieces, there is an eventual limit when we reach the quantum
level of individual atoms. Likewise, on the very tiniest scale, we expect even space
itself to be grainy. Perhaps not just space, but also time itself, is made up of finite
quanta rather than "flowing" continuously. There may be a fundamental limit to
how precisely any clock can ever subdivide time. But neither Einstein's theory nor
quantum theory, in their present forms, can tell us about the microstructure of space
and time. Twentieth-century science left this major piece of unfinished business as
a challenge for the twenty-first.
The history of science suggests that when a theory breaks down, or confronts
a paradox, the resolution will be a new paradigm that transcends what went before.
Einstein's theory and the quantum theory cannot be meshed together: both are
superb within limits, but at the deepest level they are contradictory. Until there has
been a synthesis, we certainly will not be able to tackle the overwhelming question
of what happened right at the very beginning, still less attach any meaning to the
question, "What happened before the big bang?" At the "in- . stant" of the big bang
everything was squeezed smaller than a single atom, so quantum fluctuations could
shake the entire universe.
According to superstring theory, the currently most favoured approach to a
unified theory, the particles that make up atoms are all woven from space itself. The
fundamental entities are not points, but tiny loops, or "strings," and the various sub-
nuclear particles are different modes of vibration—different
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harmonics—of these strings. Moreover, these strings are vibrating not in our
ordinary space (with three spatial dimensions, plus time) but in a space often or
eleven dimensions.
Beyond Our Space and Time
We appear to ourselves as three-dimensional beings: we can go left or right,
forward or backward, up or down, and that is all. So how are the extra dimensions,
if they exist, concealed from us? It may be that they are all wrapped up tightly. A
long hose pipe may look like a line (with just one dimension) when viewed from a
distance, but from closer up we realise that it is a long cylinder (a two-dimensional
surface) rolled up tightly; from still closer, we realise that this cylinder is made
from material that is not infinitely thin, but extends in a third dimension. By anal-
ogy, every apparent point in our three-dimensional space, if hugely magnified, may
actually have some complex structure: a tightly wound origami in several extra
dimensions.
Some of the extra dimensions could conceivably show up on a microscopic
scale in laboratory experiments (though they are probably wrapped too tightly even
for that). Even more interestingly, one extra dimension may not be wrapped up at
all: there may be another three-dimensional universe "alongside" ours, embedded in
a grander-dimensional space. Bugs crawling around on a large sheet of paper (their
two-dimensional "universe") may be unaware of a similar sheet that is parallel to it
and not in contact. Likewise, there could be another entire universe (three-
dimensional, like ours) less than a millimetre away from us, but we are oblivious to
it because that millimetre is measured in a fourth spatial dimension, and we are
imprisoned in just three.
There could have been many big bangs, even an infinity of them, not just the
one that led to "our" universe. Even our own "universe," the aftermath of our own
big bang, may extend far beyond the ten billion light years that our telescopes can
probe: it may encompass a still vaster domain, extending so far away that no light
from it has yet had time to reach us. Whenever a black hole forms, processes deep
inside it could perhaps trigger the creation of another universe, which would
expand into a space disjoint from our own. If that new universe were like ours, then
stars, galaxies, and black holes would form in it, and those black holes would in
turn spawn another generation of universes, and so on, perhaps ad infinitum.
Perhaps universes could be created in a futuristic laboratory, by imploding a lump
of material to make a small black hole, or even by crashing together atoms boosted
to very high energies in a particle accelerator. If so, the theological arguments from
design could be resuscitated in a novel guise, blurring the boundary between the
natural and the supernatural.
We have learnt, in the time since Copernicus dethroned Earth from its central
position, that our solar system is just one of billions within range of our telescopes.
Our cosmic horizons are now, once again, enlarging just as dramatically: what we
have traditionally called our universe may be just one "island" in an infinite
archipelago.
To make scientific predictions one needs to believe that nature is not
capricious, and to have uncovered some regular patterns. But these patterns need
not be fully understood. For example, the Babylonians, more than two thousand
years ago, could predict when solar eclipses were likely, because they had already
gathered data for centuries and discovered repetitive patterns in the timing of
eclipses (in particular, that they follow an eighteen-year cycle). But the
Babylonians did not know how the Sun and Moon actually moved. It was not until
the seventeenth century—the era of Isaac Newton and Edmund Halley—
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that the eighteen-year cycle was attributed to a "wobble" in the orbit of the
Moon.
Quantum mechanics works marvellously: most scientists apply it almost
unthinkingly. As my colleague John Polkinghorne has put it, "The average quantum
mechanic is no more philosophical than the average motor mechanic." But many
thoughtful scientists from Einstein onwards have found the theory "spooky" and
doubt that we have yet attained the optimum perspective on it. Interpretations of
quantum theory today may be on a "primitive" level, analogous to the Babylonian
knowledge of eclipses: useful predictions, but no deep understanding.
Some of the baffling paradoxes of the quantum world may be clarified by an
idea familiar from science fiction: "parallel universes." Olaf Stapledon's classic
novel Star Maker prefigured this concept. The star maker is a creator of universes,
and in one of his more sophisticated creations, "Whenever a creature was faced
with several possible courses of action, it took them all, thereby creating many . . .
distinct histories of the cosmos. Since in every evolutionary sequence of the cosmos
there were many creatures and each was constantly faced with many possible
courses, and the combinations of all their courses were innumerable, an infinity of
distinct universes exfoliated from every moment."
At first sight, the concept of parallel universes might seem too arcane to have
any practical impact. But it may actually offer the prospect of an entirely new kind
of computer, the quantum computer, which can transcend the limits of even the
fastest digital processor by, in effect, sharing the computational burden among a
near infinity of parallel universes.
In the twentieth century we learnt the atomic nature of the entire material
world. In the twenty-first, the challenge will be to understand the arena itself, to
probe the deepest nature of space and time. New insights should clarify how our
universe began, and whether it is one of many. On a more practical terrestrial level,
they may reveal new sources of energy latent in empty space itself.
A fish may be barely aware of the medium in which it lives and swims;
certainly, it has no intellectual powers to comprehend that water consists of
interlinked atoms of hydrogen and oxygen, each made up of still smaller particles.
The micro-structure of empty space could, likewise, be far too complex for unaided
human brains to grasp. Ideas on extra dimensions, string theory, and the like will
attract lively scientific interest in this century. We aspire to understand our cosmic
habitat—and unless we try, we certainly will not succeed—but it could be that we
stand little more chance than a fish.
The Boundaries of Time
Time, as Wells and his chrononaut knew, is a fourth dimension. Time travel
into the far future violates no fundamental physical laws. A spaceship that could
travel at 99.99 percent of the speed of light would allow its crew to "fast forward"
into the future. An astronaut who managed to navigate into the closest possible
orbit around a rapidly spinning black hole without falling in could, in a subjectively
short period, view an immensely long future time span in the external universe.
Such adventures may be unfeasible, but they are not physically impossible.
But what about travel into the past? More than 50 years ago, the great
logician Kurt Godel invented a bizarre hypothetical universe, consistent with
Einstein's theory, that allowed, "time loops," in which events in the future "cause"
events in the past that then "cause" their own causes, introducing a lot of weird-ness
to the world but no contradictions. (The film, The Terminator, in which a son sends
his father back in time to save (and
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inseminate) his mother, wonderfully combines the insights of the greatest
Austrian-American mind, Godel, with the talents of the greatest Austrian-American
body, Arnold Schwarzenegger.) Several later theorists have used Einstein's theories
to design "time machines" that might create temporal loops. But these are not
machines that would fit in a Victorian basement. Some of them need to be of
effectively infinite length; others need vast amounts of energy. Returning to the
past involves the risk of changing it in such a way that makes history internally
inconsistent by, for instance, preventing your parents from being born. Such
conundrums do not rule out time travel even in principle: they merely restrict the
time traveler's free will. But that is nothing new. Physics already constrains us: we
cannot exercise our free will by walking on the ceiling. Another option is that time
travelers could shift into a parallel universe, where events played out differently
rather than repeating themselves, as in the film Groundhog Day.
We plainly do not yet have a unified theory; and parallel universes, time
loops and extra dimensions are surely "big ideas" for twenty-first-century science.
Acknowledging this, Horgan can only sustain his pessimistic "end of science"
thesis by disparaging such theories as "ironic science." This is probably a fair
assessment of their present status, when they are a set of mathematical ideas, laced
with what seems science fiction and disengaged from experiment or observation.
But the hope is that such theories, if within our intellectual grasp, will actually
explain things about our physical world that now seem mysterious: why protons,
electrons, and other subatomic particles actually exist, and why the physical world
is governed by particular forces and laws. A unified theory may reveal some
unsuspected things, either on tiny scales, or by explaining some mysteries of our
expanding universe. Perhaps some novel form of energy latent in space can be
usefully extracted; an understanding of extra dimensions could give substance to
the cept of time travel. Such a theory will also tell us what kinds of extreme
experiments, if any, could trigger catastrophe.
The Third Frontier of Science: The Very Complex
A definitive theory for cosmos and micro world—even if it were some day
achieved—would still not presage the "end of science." There is another open
frontier: the study of things that are very complicated—above all, ourselves and our
habitat. We may understand an individual atom, and even the mysteries of the
quarks and other particles that lurk within its nucleus, but we are still perplexed by
the intricate way atoms combine to make all the elaborate structures in our
environment, especially those that are alive. The phrase "theory of everything,"
often used in popular books, has connotations that are not only hubristic, but very
misleading. A so-called theory of everything would actually offer absolutely zero
help to ninety-nine percent of scientists.
The brilliant and charismatic physicist Richard Feynman liked to emphasise
this point with a nice analogy, which actually dates back to Ɍ.ɇ. Huxley in the
nineteenth century. Imagine that you had never seen chess being played before. By
watching a few games, you could infer the rules. But in chess, learning how the
pieces move is just a trivial preliminary on the absorbing progression from novice
to grandmaster. Likewise, even if we knew the basic laws, exploring how their
consequences have unfolded over cosmic history—how galaxies and stars and
planets formed, and how here on Earth, and perhaps in many biospheres elsewhere,
atoms assembled into creatures able to reflect on their origins—is an unending
challenge.
Science is still just beginning: each advance brings into focus
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a new set of questions. I agree with John Maddox that "The big surprises will
be the answers to questions that we are not yet smart enough to ask. The scientific
enterprise is an unfinished project and will remain so for the rest of time."
It may seem presumptuous for cosmologists to pronounce confidently on
arcane and remote matters when the views of experts in long-studied everyday
subjects such as diet and child-care are manifestly little more than transient
fashions. Yet what makes things hard to understand is how complicated they are,
not how big they are. Planets and stars are big, but move in accord with simple
laws. We can understand stars, and atoms as well; but the everyday world,
especially the living world, poses a greater challenge. Dietetics is, in a real sense, a
harder science than cosmology or subatomic physics. Human beings, the most
intricately constructed entities we are aware of in the universe, are midway between
atoms and stars. It would take as many human bodies to make up ths Sun as there
are atoms in each of us.
Our everyday world poses a still greater challenge to twenty-first century
science than either the cosmos or the world of subnuclear particles. The niological
realm is the main challenge, but even simple substances behave in complex ways.
Weather patterns are manifestations of the well-understood physics of air and
water, but are exceedingly intricate, chaotic, and unpredictable; improved theories
of the micro world are no help at all to weather forecasters.
When we grapple with the complexities on our human scale, a holistic
approach proves more helpful than naive reduction- ism. Animal behaviour makes
the most sense when understood in terms of goals and survival. We can predict with
confidence that an albatross will return to its nesting place after wandering ten
thousand kilometres or more. Such a prediction would be impossible—not just in
practice, but even in principle—if we analyzed the albatross into an assemblage of
electrons, protons, and neutrons.
The sciences are sometimes likened to different levels of a tall building:
logic in the basement, mathematics on the first floor, then particle physics, then the
rest of physics and chemistry, and so forth, all the way up to psychology, sociology,
and economics in the penthouse. But the analogy is poor. The superstructures, the
"higher-level" sciences dealing with complex systems, aren't imperilled by an
insecure foundation, as a building is. There are laws of nature in the macroscopic
domain that are just as much of a challenge as anything in the micro world, and are
conceptually autonomous from it—for instance, those that describe the transition
between regular and chaotic behaviour, which apply to phenomena as disparate as
dripping water pipes and animal populations.
Problems in chemistry, biology, the environment, and human sciences
remain unsolved because scientists haven't elucidated the patterns, structures, and
interconnections, not because we don't understand subatomic physics well enough.
In trying to understand how water waves break, and how insects behave, analysis at
the atomic level doesn't help. Finding the "readout" of the human genome—
discovering the string of molecules that encode our genetic inheritance—is an
amazing achievement. But it is just the prelude to the far greater challenge of
postgenomic science: understanding how the genetic code triggers the assembly of
proteins and expresses itself in a developing embryo. Other aspects of biology,
especially the nature of the brain, pose challenges that can barely yet be formulated.
The Limits of Human Minds
Some branches of science could one day come to a halt. But this may happen
because we come up against limits of what our brains can understand, rather than
because the subject is exhausted. Physicists may never understand the bedrock
nature
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of space and time because the mathematics is just too hard; but I think our
efforts to understand very complex systems—above all, our own brains—will be
the first to hit such limits. Perhaps complex aggregates of atoms, whether brains or
machines, can never understand everything about themselves.
Computers with human-level capabilities will accelerate science, even
though they won't think the way we do. IBM's chess-playing computer Deep Blue
didn't evolve its strategy like a human player; it exploited its computational speed
to compare millions of alternative series of moves and responses, applying a
complicated set of rules, before deciding on an optimum move. This "brute force"
approach overwhelmed a world champion; likewise, machines will make scientific
discoveries that have eluded unaided human brains. For example, some substances
completely lose their electrical resistance when cooled to very low temperatures
(superconductors). There is a continuing quest to find the "recipe" for a
superconductor that works at ordinary room temperatures (that is, nearly three
hundred degrees above absolute zero; the highest superconducting temperature
achieved so far is 120 degrees). This quest involves a great deal of "trial and error,"
because nobody understands exactly what makes the electrical resistance disappear
more readily in some materials than in others.
Suppose that a machine came up with such a recipe. It might have succeeded
in the same way that Deep Blue won its chess games against Kasparov: by testing
out millions of possibilities rather than by having a human-style theory or strategy.
But it would have achieved something that would get a scientist a Nobel Prize.
Moreover, its discovery would herald a technical breakthrough that could, among
other things, lead to still more powerful computers, an example of the runaway
acceleration in technology, worrying to Bill Joy and other futurists, that could be
unstoppable when computers can augment or even supplant human brains.
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Simulations, using ever more powerful computers, will help scientists to
understand processes that we neither study in our laboratories nor observe directly.
My colleagues can already create a "virtual universe" in a computer, and do
"experiments" on it—simulating, for example, how stars form and die, and how our
Moon formed in a crash between the young Earth and another planet.
The First Life
Soon, biologists will have clarified the processes whereby combinations of
genes encode the intricate chemistry of a cell, and the morphology of limbs and
eyes. Another challenge is to elucidate how life began, and perhaps even replicate
the event, either in a laboratory or "virtually" in a computer (where evolution can be
studied much faster than in real time).
All life on Earth seems to have had a common ancestor, but how did this first
living thing come into being? What led from amino acids to the first replicating
systems, and to the intricate protein chemistry of unicellular life? The answer to this
question—the transition from the nonliving to the living—is fundamental
unfinished business for science. Laboratory experiments that try to simulate the
"soup" of chemicals on the young Earth may offer clues; so might computer
simulations. Darwin envisaged a "warm little pond." We are now more aware of the
immense variety of niches that life can occupy. The ecosystems near hot sulphurous
outwellings in the deep oceans tell us that not even sunlight is essential. So life's
begin-nings may have occurred in a torrid volcano, a location deep underground, or
even in the rich chemical mix of a dusty interstellar cloud.
Above all, we want to know whether life's emergence was in some sense
inevitable, or whether it was a fluke. Our Earth's
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cosmic importance depends on whether biospheres are rare or common,
which depends in turn on how "special" the conditions need to be for life to begin.
The answer to this key question affects the way we see ourselves and Earth's long-
range future. We are stymied, of course, by the fact that we have just a single
example, but this may change. The quest for alien life is perhaps the most
fascinating challenge for twenty-first-century science. Its outcome will influence
our concept of our place in nature as profoundly as Darwinism has over the last 150
years.
12. DOES OUR FATE HAVE COSMIC SIGNIFICANCE?
The odds could be so heavily stacked against the emergence (and
survival) of complex life that Earth is the unique abode of conscious
intelligence in our entire Galaxy. Our fate would then have truly cosmic
resonance.
Is LIFE WIDESPREAD? Or is Earth special—not just to us, for whom it is
the home planet, but for the wider cosmos?
So long as we know about only one biosphere, our own, we cannot exclude
its being unique: complex life could be the outcome of a chain of events so unlikely
that it happened only once within the observable universe, on the planet where (of
course) we are. On the other hand, life could be widespread, emerging on any
Earth-like planet (and perhaps in many other
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cosmic environments too). We still know too little about how life began and
how it evolves to decide between these two extreme possibilities. The greatest
breakthrough would be to find another biosphere: real alien life.
Unmanned explorations of the solar system in the coming decades may firm
up the odds. Since the 1960s, space probes have been sent to the other planets of
our solar system, beaming back pictures of worlds that are varied and distinctive;
but none—in sharp contrast to our own planet—seem hospitable to life. Mars is still
the main focus of attention. Probes have revealed dramatic Martian landscapes:
volcanoes up to twenty kilometres high, and a canyon six kilometres deep and
stretching four thousand kilometres across the planet. There are dried-up river beds,
even features that look like the shoreline of a lake. If surface water once flowed on
Mars, it is likely to have originated deep underground, and been forced up through
thick permafrost.
Probing Mars and Beyond
NASA's first serious search for Martian life was in the 1970s. The Viking
probes parachuted onto a barren rock-strewn desert and scooped up samples of soil;
their instruments detected no sign of even the most primitive organisms. The only
serious claim for fossil life came later, from analyses of a piece of Mars that made
its own way to Earth. Mars is being battered, as is Earth, by asteroid impacts that
throw debris out into space. Some of this debris, after wandering in orbit for many
million years, strikes Earth as meteorites. In 1996, NASA officials orchestrated a
much-hyped press conference, even attended by President Clinton, to proclaim that
a meteorite re-
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covered from the Antarctic, with chemical signatures of Martian origin,
carried traces of tiny organisms. Scientists have been backtracking ever since: "life
on Mars" may vanish just as the "canals" did a century ago. But hope of life on the
red planet has not been abandoned, though even the optimists expect little more
than dormant bacteria. Further space probes will analyse the Martian surface far
more thoroughly than Viking did, and (in later missions) return samples to Earth.
Mars is not the only target for these reconnoitres. In 2004 the European
Space Agency's Huygens probe, part of the cargo of NASAs Cassini mission, will
parachute into the atmosphere of Titan, Saturn's giant moon, seeking anything that
might be alive. There are longer-term plans to land a submersible probe on Jupiter's
moon Europa, to seek life—perhaps even with fins or tentacles—in its ice-covered
oceans.
Detecting life in two places in our solar system—which we now know is just
one of millions of planetary systems in our galaxy—would suggest that life is
common elsewhere in the universe. We would immediately conclude that our
universe (with billions of galaxies each containing billions of stars) could harbour
trillions of habitats where some kind of life (or vestiges of past life) exist. That is
why it is scientifically so important to search for life on the other planets and
moons of our solar system.
There is one key proviso, however: before drawing any inference about the
ubiquity of life, we would need to be quite sure that any extraterrestrial life had
begun independently, and that organisms had not made their way, via cosmic dust
or meteorites, from one planet to another. After all, we know that some meteorites
that hit Earth have come from Mars; if there was life on them, maybe that is how
life began on Earth. Perhaps we all have a Martian ancestry.
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Other Earths?
Even if there is life elsewhere in our solar system, few if any! scientists
expect it to be "advanced." But what about the re-1 moter cosmos? In the years
since 1995, a new field of a science has opened up: the study of other families of
planets, in orbit around distant stars. What are the prospects of life on some of
these? Few of us were surprised that these planets existed: astronomers already
knew that other stars formed as our Sun did, from a slowly spinning interstellar
cloud that contracted into a disc; the dusty gas in these other discs could
agglomerate into planets, just as happened around the new-born Sun. But until the
1990s there were no techniques sensitive enough actually to disclose any of these
faraway planets. At the time of writing, a hundred other stars like the Sun are
already known to have at least one planet; almost every month more are being
discovered. Those planets found so far, orbiting solar-type stars, are all roughly the
size of Jupiter or Saturn, the giants of our own solar system. But these are probably
just the largest members of other "solar systems" whose smaller members remain to
be discovered. A planet like Earth, three hundred times less massive than Jupiter,
would be too small and faint be revealed by present techniques, even if it were
orbiting one of the very nearest stars. To observe Earth-like planets will require
very large telescope arrays in space. NASA's flagship science programme,
"Origins," is focussed on the origin of the universe, of planets, and of life. One of
its most exciting projects will be the so-called Terrestrial Planet Finder, an array of
telescopes in space; Europeans are planning a similar project, called "Darwin."
We were all, when young, taught the layout of our own solar system—the
sizes of the nine major planets, and how they move in orbit around the Sun. But
twenty years from now, we will be
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able to tell our grandchildren far more interesting things on a starry night.
Nearby stars will no longer just be twinkling dots in the sky. We will think of them
as the Suns of other solar systems. We will know the orbits of each star's retinue of
planets, and even some topographic details of the bigger planets.
The Terrestrial Planet Finder and its European counterpart should discover
many such planets, but only as faint points of light. Nonetheless, much can be
learnt about them even without a detailed picture. Viewed from (say) fifty light
years away—the distance of a nearby star—Earth would be, in Carl Sagan's phrase,
a "pale blue dot," seeming very close to a star (our Sun) that outshines it by a factor
of many billions. The shade of blue would be slightly different, depending on
whether the Pacific ocean or the Eurasian land mass was facing us. By observing
other planets, even if we can't resolve detail on their surfaces, we can therefore infer
whether they are spinning, the length of their "day," and even their gross
topography and climate.
We will be especially interested in possible "twins" of our Earth: planets the
same size as ours, orbiting other Sun-like stars, and with temperate climates where
water neither boils nor stays frozen. By analysing such a planet's faint light, we
could infer what gases existed in its atmosphere. If ozone existed—implying that it
was rich in oxygen, as our Earth's atmosphere is—this would indicate a biosphere.
Our own atmosphere didn't start out that way, but was transformed by primitive
bacteria in its early history.
But an actual image of such a planet—one that can be displayed on the wall-
sized screens that will by then have replaced posters as room decorations—will
surely have even more im-Pact than the classic pictures of our own planet viewed
from space. Even if NASA-type programmes continued for several decades, we
won't have such pictures until after 2025. They
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will require huge mirrors in space; even an array spread over hundreds of
kilometres would give a very blurred and crude image, just able to reveal an ocean
or a continental land mass. Still further ahead, robotic fabricators may be able to
construct, in the zero gravity of space, gossamer-thin mirrors on an even more
gigantic scale. These would show more detail, and allow us to probe even further
away, increasing the chance of finding a planet that might harbour life.
Alien Life?
How far away will we have to search to find another biosphere? Does life
start on every planet in the right temperature range, where there is water, along with
other elements such as carbon? At present, such questions are open. As often in
science, lack of evidence leads to polarised and often dogmatic opinions, but
agnosticism is really the only rational attitude while we know so little about how
life began, how varied its forms and habitats could be, and what evolutionary paths
it might take.
Could some of these planets, orbiting other stars, harbour life forms far more
exotic than even optimists might expect on Mars or Europa—even something that
could be called intelligent? To firm up the odds we need a clearer understanding of
just how special Earth's physical environment had to be in order to permit the
prolonged selection process that led to the higher animal forms on Earth. Donald
Brownlee and Peter Ward, in their book Rare Earth, claim that very few planets
around other stars—even those that resembled Earth in their size and
temperatures—would provide the requisite long-term stability for the prolonged
evolution that must precede advanced life. They think that there are several other
prerequisites, which might be fulfilled only rarely. The planet's orbit
must not wander too close to its "sun," nor too far away, as it would if other
larger planets came too close and nudged it into a different orbit; its spin must be
stable (something that depends on our Moon being large); there must not be
excessive bombardment by asteroids; and so forth.
But the greatest uncertainties lie in the province of biology, not astronomy.
First, how did life begin? I think that there is a real chance of progress here, so that
we will know whether it is a "fluke," or whether it is nearly inevitable in the kind of
initial "soup" expected on a young planet. But there is a second question: Even if
simple life exists, what are the odds against it evolving into something that we
would recognise as intelligent? This is likely to prove far more intractable. Even if
primitive life were common, the emergence of "advanced" life may not be.
We know, in outline, the key stages in life's development here on Earth. The
simplest organisms seem to have emerged within one hundred million years of the
final cooling of Earth's crust after the last major impact, about four billion years
ago. But about two billion years seems to have elapsed before the first eukaryotic
(nucleated) cells appeared, and a further billion before multicellular life. Most of
the standard body types seem to have first appeared during the "Cambrian
explosion" just over half a billion years ago. The immense variety of creatures on
land emerged since that time, punctuated by major extinctions, such as the event
sixty-five million years ago that wiped out the dinosaurs.
Even if simple life existed on many planets around nearby stars, complex
biospheres like Earth's could be rare: there could be some key hurdle in evolution
that is hard to surmount. Perhaps it is the transition to multicellular life. (The fact
that simple life on Earth seems to have emerged quite quickly, whereas even the
most basic multicellular organisms
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took nearly three billion years, suggests that there may be severe barriers to
the emergence of any complex life.) Or the biggest hurdle could come later. Even in
a complex biosphere the emergence of human-level intelligence isn't guaranteed. If,
for instance, the dinosaurs hadn't been wiped out, the chain of mammalian
evolution that led to Homo sapiens may have been foreclosed, and we cannot
predict whether another species would have taken our role. Some evolutionists
regard the emergence of intelligence as a contingency, even an unlikely one. Others
dissent from this line, however. In the latter camp is my Cambridge colleague
Simon Conway Morris, an authority on the extraordinary variety of Cambrian life
forms in the Burgess Shale, in the Canadian Rockies in British Columbia. He is
impressed by the evidence for "convergence" in evolution (for instance, the fact that
Australasian marsupials have placental counterparts on other continents) and argues
that this might almost guarantee the emergence of something like us. He writes,
"For all of life's plenitude there is a strong stamp of limitation, imparting not only a
predictability to what we see on Earth, but by implication elsewhere."
Perhaps, more ominously, there could be a crucial hurdle at our own present
evolutionary stage, the stage when intelligent life starts to develop technology. If
so, the future development of life depends on whether humans survive this phase.
This does not mean that Earth has to avoid a disaster, only that before this happens,
some human beings or advanced artefacts will have spread beyond their home
planet.
Searches for life will justifiably focus on Earth-like planets orbiting long-
lived stars. But science fiction authors remind us that there are more exotic
alternatives. Perhaps life can flourish even on a planet flung into the frozen
darkness of interstellar space, whose main warmth comes from internal
radioactivity (the process that heats Earth's core). There could be diffuse living
structures, freely floating in interstellar clouds; such entities would live (and, if
intelligent, think) in slow motion, but nonetheless may come into their own in the
long-range future. No life would survive on a planet whose central Sun-like star
became a giant and blew off its outer layers. Such considerations remind us of the
transience of inhabited worlds, and also that any seemingly artificial signal could
come from superintel-ligent (though not necessarily conscious) computers, created
by a race of alien beings that had long since died out.
Alien lntelligence: Visits or Signals?
If advanced life is widespread, we must confront the famous question first
posed by the great physicist Enrico Fermi: Why haven't they visited Earth already?
Why aren't they, or their artefacts, staring us in the face? This argument gains
further weight when we realise that some stars are billions of years older than our
Sun: if life were common, its emergence should have had a "head start" on planets
around these ancient stars. The cosmologist Frank Tipler, perhaps the most vocal
proponent of the view that we are alone, doesn't suggest that aliens would
themselves have travelled interstellar distances. He argues, however, that at least
one alien civilisation would have developed self-reproducing machines and
launched them into space. These machines would spread from planet to planet,
multiplying as they went; they would spread through the Galaxy within ten million
years, a time far shorter than the "head start" that some of the other civilisations
could have had. (Of course, there have been recurrent contentions that UFOs have
indeed visited us; some people claim to have been abducted by aliens. In the 1990s,
their favoured "visiting card" a pattern of "crop circles" in cornfields, mainly in
southern
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England. Along with most scientists who have studied these reports, I am
utterly unconvinced. Extraordinary claims need extraordinary evidence to support
them, but in all these cases the evidence is flimsy. If aliens really had the
brainpower and technology to reach Earth, would they merely despoil a few corn-
fields? Or content themselves with briefly abducting a few well-known cranks?
Their manifestations are as banal and unconvincing as the messages from the dead
that used to be reported in the heyday of spiritualism a hundred years ago.)
Maybe we can rule out visits by human-scale aliens, but if an extraterrestrial
civilisation had mastered nanotechnology and transferred its intelligence to
machines, the "invasion" might consist of a swarm of microscopic probes that could
have evaded notice. Even if we haven't been visited at all, we shouldn't, despite
Fermi's question, conclude that aliens don't exist. It would be far easier to send a
radio or laser signal than to traverse the mind-boggling distances of interstellar
space. We are already able to send signals that could be picked up by an alien
civilisation; indeed, equipped with large radio antennae they could pick up the
strong signals from antiballistic missile radars, as well as the combined output of all
our TV transmitters.
Searches for extraterrestrial intelligence (SETI) are being spearheaded by the
SETI Institute, at Mountain View, California; its work is supported by hefty
donations from Paul Allen, cofounder of Microsoft, and other private benefactors.
Any interested amateur with a home computer can download and analyse a short
stretch of the data stream from the institute's radio telescope. Millions have taken
up this offer, each inspired by the hope of being first to find "ET." In the light of
this broad public interest, it seems surprising that SETI searches have had such a
hard time getting public funding, even at the level of the tax revenues from a single
science fiction movie. If I were an American scientist testifying before congress I
would be happier requesting a few million dollars for SETI than seeking funds for
more specialised science, or indeed for conventional space projects.
It makes sense to listen, rather than transmit. Any two-way exchange would
take decades, so there would be time to plan a measured response. But in the long
run, a dialogue could develop. The logician Hans Freudental proposed an entire lan-
guage for interstellar communication, showing how it could start with the limited
vocabulary needed for simple mathematical statements, and gradually build up and
diversify the realm of discourse. A manifestly artificial signal, whether it was in-
tended to be decoded or was part of some cosmic cyberspace that we were
eavesdropping on, would convey the momentous message that intelligence (though
not necessarily consciousness) wasn't unique to Earth.
If evolution on another planet in any way resembled the "artificial
intelligence" scenarios conjectured for the twenty-first century here on Earth, the
most likely and durable form of "life" may be machines whose creators had long
ago been usurped or become extinct. The only type of intelligence we could detect
would be one that led to a technology that we could recognise, and that could be a
minor and atypical fraction of the totality of extraterrestrial intelligence. Some
"brains" may package reality in a fashion that we can't conceive and have a quite
different perception of reality. Others could be uncommunicative: living
contemplative lives, perhaps deep under some planetary ocean, doing nothing to
reveal their presence. Still other "brains" could actually be assemblages of
superintelligent "social insects." There may be a lot more out there than we could
ever detect. Absence of evidence wouldn't be evidence of absence.
We know too little about how life began, and how it evolves, to be able to
say whether alien intelligence is likely or not. 168
The cosmos could already be teeming with life: if so, nothing that happens
on Earth would make much difference to life's long-range cosmic future. On the
other hand, the emergence of intelligence may require such an improbable chain of
events that it is unique to our Earth. It may simply not have occurred anywhere
else, not around even one of the trillion billion other stars within range of our
telescopes.
Nor can we judge how best to search for intelligent life. In earlier chapters I
have emphasised that we cannot even be sure what the dominant form of
intelligence on Earth will be, even a century from now. What prospect could we
have of envisaging what might be spawned from another biosphere with a billion-
year head start on us? We know too little to lay confident odds on what may exist
or how it might manifest itself, and so we should search for anomalous radio
emissions, optical flashes, and absolutely any type of signal that we have
instruments to detect.
In some ways it would be disappointing if searches for alien intelligence
were doomed to fail. On the other hand, such a failure would boost our cosmic self-
esteem: if our tiny Earth were a unique abode of intelligence, we could view it in a
less humble perspective than it would merit if the Galaxy already teemed with
complex life.
13. BEYOND EARTH
If robotic probes and fabricators spread through the solar system,
would any humans follow? Communities away from Earth would be
established (if at all) by risk-taking individualist pioneers. Travel beyond the
solar system is a far remoter, posthuman, prospect.
AN ICONIC IMAGE FROM THE 1960S was the first photograph from
space, showing our spherical Earth. Jonathan Schell suggests that this picture
should be complemented by another one, which focuses on our planet but is
extended in time rather than in space: "The view that counts is the one from Earth,
from within life. . . . From this Earthly vantage Point another view—one even
longer than the one from space—opens up. It is the view of our children and
grandchildren, and of all the future generations of humankind, stretch-
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ing ahead of us in time. . . . The thought of cutting off life's flow, of
amputating this future, is so shocking, so alien to nature, and so contradictory to
life's impulse that we can scarcely entertain it before turning away in revulsion and
disbelief."
Is it worth taking precautions to ensure that whatever may happen,
something survives of humanity? Most of us care about the future, not just because
of a personal concern with children and grandchildren, but because all our efforts
would be devalued if they were not part of a continuing process, if they did not
have consequences that resonated into the far future.
It would be absurd to claim that emigration into space is an answer to the
population problem, or that more than a tiny fraction of those on Earth will
themselves ever leave it. If some disaster reduced humanity to a far lower
population, living in primitive conditions in a devastated wasteland, the survivors
would still find Earth's environment more hospitable than that of any other planet.
Nonetheless, even a few pioneering groups, living independently of Earth, would
offer a safeguard against the worst possible disaster—the foreclosure of intelligent
life's future through the extinction of all humankind.
The ever-present slight risk of a global catastrophe with a "natural" cause
will be greatly augmented by the risks stem-ming from twenty-first-century
technology. Humankind will remain vulnerable so long as it stays confined here on
Earth. Is it worth, in the spirit of Pascal's wager, insuring against not just natural
disasters but the probably much larger (and certainly growing) risk of the human-
induced catastrophes discussed in earlier chapters? Once self-sustaining
communities exist away from Earth—on the Moon, on Mars, or freely floating in
space—our species would be invulnerable to even the worst global disasters.
So how feasible would it be to establish a sustainable habitat elsewhere in
the solar system? How long will it be before people return to the Moon, and
perhaps explore still further afield?
Will Manned Space Flight Revive?
Those of us who are now middle-aged can remember the murky live TV
pictures of Neil Armstrong's "one small step." In the 1960s, President Kennedy's
programme to "land a man on the Moon before the end of the decade, and return
him safely to Earth" took space flight from the corn-flakes packet to reality. And it
seemed just a beginning. We imagined follow-up projects: a permanent "lunar
base," rather like the existing base at the South Pole; or even huge "space hotels"
orbiting Earth. Manned expeditions to Mars seemed a natural next step. But none of
these has happened. The year 2001 didn't resemble Arthur C. Clarke's depiction,
anymore than 1984 (fortunately) resembled Orwell's.
Rather than being a precursor for a continuing and ever more ambitious
programme of manned space flight, the Apollo moon landing programme was a
transient episode, motivated primarily by the urge to "beat the Russians."
The last lunar landing was in 1972. Nobody much under the age of thirty-
five can remember when men walked on the Moon. To young people, the Apollo
programme is a remote historical episode: they know the Americans landed men on
the Moon, just as they know the Egyptians built the pyramids; but the motivations
seem almost as bizarre in the one case as in the other. The 1995 film Apollo 13, a
"docudrama" starring Tom Hanks, about the near disaster that befell James Lovell
and his crew on a voyage round the Moon, was for me (and I suspect for many
others of similar vintage) an evocative reminder of an episode we had followed
anxiously at the time. But to a young
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audience, the outdated gadgetry and the traditional "right stuff" values
seemed almost as antiquated as a traditional "Western."
The practical case for manned space flight was never strong, and it gets ever
weaker with each advance in robotics and miniaturisation. The use of space for
communications, meteorology, and navigation has forged ahead, benefiting from
the same technical advances that have given us mobile phones and high-
performance laptop computers here on Earth. Space exploration for scientific
purposes can be better (and far more cheaply) carried out by unmanned probes.
Huge numbers of miniaturised robotic probes—"intelligent machines"—will,
twenty-five years from now, be dispersed through the solar system, sending back
images of planets, moons, comets, and asteroids, revealing what they are made of,
and perhaps constructing artefacts from the raw materials to be found in them.
There may be long-term economic benefits from space, but these will be
implemented by robotic fabricators, not by people.
But what is the future for manned space flight? In the 1990s Russian
cosmonauts spent months, even years, circling Earth in the increasingly decrepit
Mir space station. Having far surpassed its design lifetime, Mir ended its mission in
2001 with a final splashdown in the Pacific Ocean. Its successor, the International
Space Station (ISS) will be the most expensive artefact ever constructed, but it is a
"turkey" in the sky. Even if it is finished, something that seems uncertain, given the
immense and ever-rising costs, and prolonged delays, it can do nothing to justify its
price tag. Thirty years after men walked on the Moon, a new generation of
astronauts is going round and round Earth, in more comfort than Mir offered, but
much more expensively. At the time of writing, the number of astronauts on board
has been scaled back to three, for reasons of safety and finance: they will be
preoccupied with "housekeeping" tasks, making it even less likely that anyone on
board will pursue any serious or interesting projects. Indeed, it is as sub-optimal to
do most science from the ISS as it would be to do ground-based astronomy from a
boat. Even in the US, the scientific community was firmly opposed to the ISS, and
abandoned campaigning against it only when the political momentum became
unstoppable. It is sad that they weren't listened to: it is a wasteful political failure
that government funds couldn't have been channelled towards the same aerospace
companies for alternative projects that were either useful or inspirational. The ISS
is neither.
There is only one reason to applaud the ISS: if one believes that in the long
run space travel will become routine, this continuing programme ensures that the
forty years of experience of manned space flight gained by US and Russia is not
dissipated. A revival in manned space flight must await changes in technology
and—perhaps even more—changes in style. Present launching techniques are as
extravagant as air travel would be if the plane had to be rebuilt after every flight.
Space flight will become affordable only when its technology comes closer to that
of supersonic aircraft. Tourist trips into orbit may then become routine. Already,
the American financier Dennis Tito and the South African software magnate Mark
Shuttleworth have spent twenty million dollars in return for a week in the ISS.
There is a line-up of others willing to follow these "space tourists," even at that
price; there would be far more if the tickets got cheaper.
Indeed, private individuals won't, in the long run, restrict themselves to the
role of passengers passively circling Earth. When this kind of escapade palls,
seeming too tame and routine, some will yearn to go further. Manned expeditions
into deep space could be entirely funded by private individuals or consortia,
perhaps indeed becoming the province of wealthy adventurers prepared, like test
pilots or Antarctic explorers, to
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accept high risks to boldly explore the far frontier and experience thrills
beyond those provided by large yachts or round the world ballooning. The Apollo
programme was a government-funded quasi-military enterprise; future expeditions
could he quite different in style. If high-tech billionaires like Bill Gates or Larry
Ellison seek challenges that won't make their later life seem an anticlimax, they
could sponsor the first lunar base or even an expedition to Mars.
The "Cheap" Route to Mars
If Martian exploration were initiated in the near future, it might well follow
the format advocated by the maverick American engineer Robert Zubrin. In
response to discouraging claims from NASA that an expedition would cost over
one hundred billion dollars, Zubrin proposed a cut-price "Mars direct" strategy that
would bypass the International Space Station. He aimed to evade one of the main
problems of earlier schemes: the need to carry, on the outward journey, all the fuel
for a return trip. The proposal, presented in his book The Case for Mars, involves
first sending directly to Mars an unmanned probe that will manufacture the fuel for
the return journey. It would carry a chemical processing plant, a small nuclear reac-
tor, and a rocket capable of bringing back the first group of explorers. This rocket
would not be fully fuelled: its tanks would be filled with pure hydrogen. The
nuclear reactor (pulled by a small tractor that would also be part of the first
payload) would then generate energy for the chemical plant, which would use
hydrogen to convert carbon dioxide from the Martian atmosphere into methane and
water. The water would then be broken down, the oxygen stored, and the hydrogen
recycled to make more methane. The return rocket fuel would then be methane and
oxygen. Six tonnes of hydrogen would allow one hundred tonnes of methane to be
made, enough to fuel the astronauts' return rocket. (Of course, if water could be
extracted from permafrost that was not too deep below the surface, part of this
process could be bypassed.)
Two years later, a second and third spacecraft would be launched. One
would carry a cargo similar to that of the earlier craft, while the other would contain
the crew, along with sufficient provisions for a sojourn on Mars of up to two years.
The manned craft would go on a faster trajectory than that carrying the cargo. This
means that the crew need not be launched until (and unless) the cargo was safely on
its way, but they could nonetheless reach Mars before the cargo arrived. If through
some mishap they landed far away from the intended site (where the first instalment
of cargo was located), there would still be time to divert the second cargo craft to
the actual landing site, so that wherever they landed, the crew would have supplies.
Once this path-finding mission was accomplished, there could be one or more
follow-ups every two years, gradually building up infrastructure.
Would anyone want to go? There may be a parallel here with terrestrial
exploration, which was driven by a variety of motives. The explorers who set out
from Europe in the fifteenth and sixteenth century were bankrolled mainly by
monarchs, in the hope of recouping exotic merchandise or colonising new territory.
Some, for instance Captain Cook on his three eighteenth-century expeditions to the
South Seas, were publicly funded, at least in part as a scientific enterprise. And for
some early explorers—generally the most foolhardy of all—the enterprise was
primarily a challenge and adventure: the motivation of present-day mountaineers
and round-the-world sailors. The first travellers to Mars, or the first long-term
denizens ɨf a lunar base, could be impelled by any of these motives. The
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risks would be high; but in fact, no space travellers would be venturing into
the unknown to the extent that the great terrestrial navigators were. These early
ocean voyagers had far less foreknowledge of what they might encounter, and
many died in the enterprise. Nor would any space travellers be cut off from human
contact. There would admittedly be a thirty-minute turnaround for messages to and
from Mars. But it took months for traditional explorers to send messages home; and
some—Captain Scott and other polar pioneers among them— had no such contact
at all.
The stakes are high in opening up new worlds. It seems taken as an axiom
that all should return. But maybe the most determined pioneers would be prepared
to accept—as many Europeans willingly did when they set out for the New
World—that there would be no return. Many could be found who would sacrifice
themselves in a glorious and historic cause; by forgoing the option of ever returning
home, they would slash the cost by obviating the need to carry rocket casings and
hydrogen for the return trip. A Martian base would develop more quickly if those
constructing it were content with oneway tickets.
Futurists and space enthusiasts often urge that "humanity" or "the nation"
should choose to do something. Space exploration indeed began as a quasi-military
enterprise funded by governments. But this rhetoric is inappropriate to manned
space exploits in the twenty-first century. Most great innovations and achievements
were initiated not because they were a national goal, still less a goal of humanity,
but because of economic motivation or simply personal obsession.
The enterprise will become far cheaper and less precarious when propulsion
systems are more efficient. It currently takes several tonnes of chemical fuel to
propel one tonne of payload away from the grip of Earth's gravity. Space travel is
difficult primarily because the trajectory has to be planned with high precision in
order to minimise fuel consumption. But if there were, say, ten times more thrust
for each kilogram of fuel, then midcourse adjustments could be made whenever
necessary, just as we do when driving along a winding road. Keeping a car on the
road would be a high-precision enterprise if the journey had to be programmed
beforehand, with no chance of adjustments on the way. If one could be profligate
with power and fuel, space travel would be an almost unskilled exercise. The
destination (the Moon, Mars, or an asteroid) is in clear view. One just has to steer
towards it and use retrojets to brake by the right amount at journey's end.
We don't yet know what kind of novel propulsion systems will prove most
promising: solar and nuclear power are the two obvious near-term options. It would
greatly help if the propulsion system and the fuel needed for escape from Earth's
gravity could be located on the ground rather than having to be part of the cargo.
One possibility is immensely powerful ground-based lasers. Another is a space
elevator, a wire made of carbon fibre extending more than thirty-five thousand
kilometres up into space and held aloft by a geostationary satellite. (Carbon
nanotubes have a tensile strength that is high enough. Very thin carbon "yarns"
have already been made that are up to thirty centimetres long; the challenge is to
fabricate tubes of enormous length, or devise techniques for weaving many into a
very long wire that retains the strength of separate fibres.) This "elevator" would
allow payloads and passengers to be hoisted from the grip of Earth's gravity by
power supplied from the ground. The rest of the voyage could be powered by a
low-thrust (perhaps nuclear) rocket.
Before human beings venture into deep space, the entire solar system will
have been mapped and probed by flotillas of tiny robotic craft, controlled by the
ever more powerful and minia-
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turised "processors" that nanotechnology will provide. A manned expedition
to Mars will have been preceded by the cargoes of provisions envisaged by Zubrin,
and perhaps also by seeds of plants designed to thrive and multiply on the red
planet. Freeman Dyson envisages genetically engineered "designer trees" that could
grow a transparent membrane around themselves that functions as a greenhouse.
Brute-force methods have been proposed for "terraforming" the entire
surface of Mars to render it more habitable. It could be warmed by injecting
greenhouse gases into its tenuous atmosphere, or placing huge mirrors in orbit to
direct more sunlight to the poles, or even covering tracts of the Martian surface
with something black to absorb sunlight—soot or powdered basalt. Terraforming
would take centuries; but within a century there could be a permanent presence on
localised bases. Once the infrastructure was there, two-way trips would become less
costly and could be more frequent.
Issues of environmental ethics may loom large. Would it be acceptable to
exploit Mars, as happened when (with tragic consequences for the Native
Americans) the pioneer settlers vanced westward across the United States? Or
should it be preserved as a natural wilderness, like^the Antarctic? The answei
should I think depend on what the pristine state of Mars actually is. If there were
any life there already—especially if it had different DNA, testifying to quite
separate origin from any life on Earth—then there would be widely voiced views
that itj should be preserved as unpolluted as possible. What might actually happen
would depend on the character of the first expeditions. If they were governmental
(or international), Antarctic-style restraint might be feasible. On the other hand, if
the explorers were privately funded adventurers of a free-enterprise (even anarchic)
disposition, the Wild West model would, whether we liked it or not, be more likely
to prevail.
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The focus will not stay exclusively on the Moon and Mars. Life could
eventually spread and diversify among comets and asteroids, even in the cold outer
reaches of the solar system: the vast number of small bodies in the solar system
have, in toto, a far larger habitable surface than the planets.
An alternative would be to construct an artificial habitat, freely floating in
space. This option was studied back in the 1970s by Gerard O'Neill, an engineering
professor at Princeton University. He envisaged a spacecraft in the shape of a vast
cylinder, slowly spinning around its axis. The occupants would live on the inside of
its walls, pinned to them by the artificial gravity generated by its spin. The
cylinders would be big enough to have an atmosphere, even perhaps clouds and
rain, and could accommodate tens of thousands in an environment that, in O'Neill's
perhaps fanciful sketches, resembled a leafy Californian suburb. The material to
build these gargantuan structures would have to be "mined" from the Moon or from
asteroids. O'Neill made the valid point that once large-scale robotic engineering
projects can be carried out in space, using raw materials that need not be lifted from
Earth, it becomes feasible to build artificial space platforms on a very ample scale.
O'Neill's specific scenarios may become technically feasible, but they will remain
sociologically implausible. A single fragile structure containing tens of thousands
of people would be even more vulnerable than integrated communities down on
Earth to a single act of sabotage. A more dispersed set of smaller-scale habitats
would offer more robust chances of survival and development.
In the second half of the twenty-first century there could be hundreds of
people in lunar bases, just as there now are at the South Pole; some pioneers could
already be living on Mars, or
180
else on small artificial habitats cruising the solar system, attaching
themselves to asteroids or comets. Space will also be pervaded by robots and
intelligent "fabricators," using raw material mined from asteroids to construct
structures of ever- expanding scale. I am not especially advocating these develop-
ments, but they nonetheless seem plausible, both technically and sociologically.
The Far Future
Still further ahead, in future centuries, robots and fabricators could have
pervaded the entire solar system. Whether human beings will themselves have
joined this diaspora is harder to predict. If they did, communities would develop in
a manner that eventually made them quite independent of Earth. Unconstrained by
any restrictions, some would surely exploit the full range of genetic techniques and
diverge into new species. (The constraint due to lack of genetic diversity in small
groups could be overcome by artificially induced variations in the genome.) The
diverse physical conditions—very different on Mars, in the asteroid belt, and in the
still colder far reaches of the solar system—would give renewed impetus to
biological diversification.
Although a contrary view is often expressed, the expanses of space offer
little prospect of a solution to resource or population problems on Earth: these will
have to be sorted out down here, if the problem isn't rendered nugatory by one of
the disastrous setbacks to terrestrial civilisation conjectured in earlier chapters. The
populations in space may eventually grow exponentially, but this will be because of
their autonomous growth rather than by "emigration" from Earth. Those going into
space will be impelled by an exploratory urge. But their choices will have epochal
consequences. Once the threshold is crossed when there is a self-sustaining level of
life in space, then life's long-range future will be secure irrespective of any of the
risks on Earth (with the single exception of the catastrophic destruction of space
itself). Will this happen before our civilisation disintegrates, leaving the prospect as
a might-have-been? Will self-sustaining space communities be established before a
catastrophe sets back the prospect of any such enterprise, perhaps foreclosing it for
ever? We live at what could be a defining moment for the cosmos, not just for our
Earth.
The beings that could, within a few hundred years, occupy sites in our solar
system would all be recognisably humanoid, though they would be complemented
(and probably, in the most inhospitable locations, vastly outnumbered) by robots
with human intelligence. However, travel beyond the solar system, through
interstellar space, would, if it ever happened, be a posthuman challenge. Voyages
would initially involve robotic probes. The journey would last many human
generations and require a self-contained community, or suspended animation of any
living intelligence. Alternatively, genetic material, or blueprints downloaded into
inorganic memories, could be launched into the cosmos in miniature spacecraft.
They could be programmed to land on promising planets, and duplicate copies of
themselves, thereby starting a diffusion through the entire Galaxy. There could
even be laser transmission of "encoded" information (a kind of "space travel" that
could happen at the speed of light) which could trigger the assembly of artefacts or
the "seeding" of living organisms in propitious locations. Such concepts confront us
with profound issues about the limits of information storage, and philosophical
implications of identity. This would be as epochal an evolutionary transition as that
which led to land-based life on Earth. But it could still be just the beginning of
cosmic evolution.
181
A Gigayear Perspective
A hackneyed anecdote among astronomy lecturers describes a worried
questioner asking: "how long did you say it would be before the sun burnt the Earth
to a crisp?" On receiving the answer, "six billion years," the questioner responds
with relief: "thank God for that, I thought you said six million." What happens in
far-future aeons may seem blazingly irrelevant to the practicalities of our lives. But
I don't think the cosmic context is entirely irrelevant to the way we perceive our
Earth and the fate of humans.
The great biologist Christian de Duve envisages that "The tree of life may
reach twice its present height. This could happen through further growth of the
human twig, but it does not have to.There is plenty of time for other twigs to bud
and grow, eventually reaching a level much higher than the one we occupy while
the human twig withers. . . . What will happen depends to some extent on us, since
we have now have the power of decisively influencing the future of life and hu-
mankind on Earth."
Darwin himself noted that "not one living species will transmit its unaltered
likeness to a distant futurity". Our own species may change and diversify faster
than any predecessor, via intelligently controlled modifications, not by natural
selection alone. Long before the Sun finally licks Earth's face clean, a teeming
variety of life or its artifacts could have spread far beyond its original planet;
provided that we avoid irreversible catastrophe before this process can even
commence. They could look forward to a near-infinite future. Wormholes, extra di-
mensions and quantum computers open up speculative scenarios that could
transform our entire universe eventually into a "living cosmos."
183
The first aquatic creatures crawled onto dry land in the Silurian era, more
than three hundred million years ago They may have been unprepossessing brutes,
but had they been clobbered the evolution of land-based fauna would have been
jeopardised. Likewise, the post-human potential is so immense that not even the
most misanthropic amongst us would countenance its being foreclosed by human
actions.
14. EPILOGUE
TRADITIONAL WESTERN CULTURE envisaged a beginning and an end of
history, but a constricted timespan—just a few thousand years—in between. (Many,
however, queried the exactitude of the Archbishop of Armagh, James Ussher, who
famously dated the creation at Saturday afternoon on 22nd October, 4004 B.c.E.)
Moreover, history was widely believed to have already entered its final millennium.
For the 17th century essayist Sir Thomas Browne "the world itself seems in the
wane. A greater part of Time is spun than is to come."
To Ussher's mind, the creation of the world and the creation of humanity
were within a week of one another; to our modern minds, the two events are
unimaginably far apart. There was a vast absence before us, and its record stares out
at us from every rock. The evolution of Earth's biosphere can now be traced back
several billion years: the future of our physical universe is reckoned to be more
extended still, perhaps even infinite. But despite these expanded horizons, both past
and future, one timescale has contracted: pessimistic estimates of how
185
186
long our civilization has to run, before crumbling, or even undergoing a
terminal apocalypse, are shorter than would have been gauged by our forebears
who devotedly added bricks to cathedrals that would not be finished in their
lifetime. Earth itself may endure, but it will not be humans who cope with the
scorching of our planet by the dying sun; nor even, perhaps, with the exhaustion of
Earth's resources.
If our solar system's entire lifecycle, from its birth in a cosmic cloud to its
death-throes in the Sun's terminal flare-up, were to be viewed "fast forward" in a
single year, then all recorded history would be less than a minute in early June. The
twentieth century would flash past in a third of a second. The next fraction of a
second, in this depiction, will be "critical": in the twenty-first century, humanity is
more at risk than ever before from misapplication of science. And the
environmental pressures induced by collective human actions could trigger catas-
trophes more threatening than any natural hazards.
For several recent decades, we were vulnerable to a nuclear holocaust. We
escaped, but in retrospect our survival seems due as much to good luck as to
intrinsically favourable odds. Moreover, recent knowledge (especially in biology)
has opened up non-nuclear dangers that could be even more sombre in the next
half-century. Nuclear weapons give an attacking nation a devastating advantage
over any feasible defense. New sciences will soon empower small groups, even
individuals, with similar leverage over society. Our increasingly interconnected
world is vulnerable to new risks; "bio" or "cyber," terror or error. These risks can't
be eliminated: indeed it will be hard to stop them from growing without
encroaching on some cherished personal freedoms.
The benefits opened up by biotechnology are manifest, but they must be
balanced against the accompanying hazards and ethical constraints. Robotics or
nanotechnology will also involve trade-offs: they could have disastrous or even
uncontrollable consequences when misapplied. Experimenters should be cautious
in"pushing the envelope" of science; even if there were a case for putting the brakes
on some research, a moratorium could never be effectively enforced worldwide.
Neither speculative thinkers like H.G. Wells nor his scientific
contemporaries had much success in foreseeing the highlights of twentieth-century
science.The present century is even less predictable because of the possibility of
altering or supplementing the human intellect. But any entirely unsuspected new
advances may well pose novel hazards too. Special responsibility lies with
scientists themselves: they should be mindful of how their work might be applied,
and do all they can to alert the wider public to potential perils.
A key challenge is to understand the nature of life; how it began, and
whether it exists beyond Earth. (There is certainly no other scientific question that I
would personally be more eager to see answered). Alien life may be discovered—
even, conceivably, alien intelligence. Our planet could be one of millions that are
inhabited: we may live in a biofriendly universe already teeming with life. If so, the
most epochal happenings on Earth, even our utter extinction,would barely register
as a cosmic event. In the quaint words of the eighteenth-century astronomer and
mystic,Thomas Wright of Durham:"In this great Celestial Creation, the Catastrophy
of a World, such as ours, or even the total Dissolution of a System of Worlds, may
possibly be no more to the great Author of Nature, than the most common Accident
in Life with us, and in all Probability such final and general Dooms Days may be as
frequent there, as even Birth-Days or Mortality with us upon this Earth."
But it could turn out that the odds are heavily stacked against the emergence
of life, so that our biosphere is the unique abode
188
of intelligent and self-aware life within our Galaxy. Our small Earth's fate
would then have a significance that was truly cosmic—an importance that would
reverberate through the whole of Thomas Wright's "Celestial Creation."
Our primary concerns are naturally with the fate of our present generation,
and to reduce the threats to us. But for me, and perhaps for others (especially those
without religious belief), a cosmic perspective strengthens the imperative to cherish
this "pale blue dot" in the cosmos. It should also motivate a circumspect attitude
towards technical innovations that pose even a small threat of a catastrophic
downside.
The theme of this book is that humanity is more at risk than at any earlier
phase in its history. The wider cosmos has a potential future that could even be
infinite. But will these vast expanses of time be filled with life, or as empty as the
Earth's first sterile seas? The choice may depend on us, this century.
NOTES
Chapter 1
3 "... real life Dr. Strangeloves..." The most prominent nuclear
strategist was Herman Kahn, author of On Thermonuclear War (Princeton
University Press, i960).
4 "... words of Gregory Benford ..." Deep Time, by Gregory Ben-
ford, is published by Avon Books, NY, (1999).
5 "... mathematician and philosopher Frank Ramsey..." Foundations
of Mathematics and other Logical Essays, by F. P. Ramsey, London, Kegan
Paul, Trench and Trubner, p. 291. Published posthumously in 1931.
6 "About 4.5 billion years ago ..." For a fuller account of cosmic history, see
my book Our Cosmic Habitat (Princeton University Press and Phoenix paperback,
2003).
Chapter 2
9 "•.. Ƚ902 lecture entitled 'Discovery of the Future' . . ." H.G. Wells's Royal
Institution lecture, given on 24 January 1902, was, unusually, reprinted in full in the
journal Nature. The programme note described him as "H.G. Wells, ȼ Sc": he was
inordinately proud of the academic degree he had gained by external study at
London University.
189
192
Notes to Pages 32-43
Notes to Pages 43-54
193
smoke and soot released, and how long it would stay in the atmosphere, were
the subject of subsequent controversy.
32 "The basic reason .. ." Nuclear Illusion and Reality, by Solly Zuck-erman.
The quotations are taken from pages 103 and 107.
34 "The total of excess material. . ." Megatons and Megawatts, by R. L.
Garwin and G. Charpak, Random House (2002).
36 "... argues that undetectable tests ..." Technical Issues Related to the
Comprehensive Nuclear Test Ban Treaty, a report of the Committee on
International Security and Arms Control, National Academy of Sciences, published
in 2002.
37 ". .. founded a series of conferences.. . ." Information on the Pug-
wash conferences and their history is accessible on http://www.
pugwash.org/. The obscure village after which the conferences were named had
incongruous associations in the UK, where "Captain Pugwash" was a well-known
cartoon character on children's television.
38 "cease and desist..." The quotation is from an article by Hans
Bethe in the New York Review of Books.
38 "... manifesto stressing the urgency..." The Einstein-Russell
manifesto was recently reprinted, with commentary, by the Pugwash
organisation.
39 "an international group convened . . ." The Canberra Commis-
sion on the Elimination of Nuclear Weapons presented its report to the
Australian government in 1997. In addition to those mentioned in the text, its
members included General Lee Butler, former head of US Strategic Air Command,
and an eminent British soldier, Field Marshal Carver.
40 "... two most prominent personalities. ..." For a detailed account
see Brotherhood of the Bomb: The Tangled Lives and Loyalties of Robert
Oppenheimer, Ernest Lawrence and Edward Teller, by Gregg Herken, Henry Holt
(2002).
Chapter 4
43 "... portrayed devastation ..." Tom Clancy is notable for the pre-
science and technical fidelity of his plot lines. An earlier novel, Debt of
Honor, featured the use of an airliner as a missile to attack the Capitol building in
Washington.
44 "With modern weapons-grade uranium ..." Luis Alvarez is quoted on the
website of the Nuclear Control Institute, Washington, DC.
44 "A nuclear explosion at the World Trade Center ..." This scenario, along
with other related material, is discussed in Avoiding Nuclear Anarchy, edited by
G.T. Allison (BCSIA Studies in International Security, 1996).
44 "We have slain the dragon ..." James Wolsey was speaking at US
Senate hearings in February 1993.
45 ".. . crash onto the containment vessel." A brief survey of these
risks (with references) is Nuclear Power Plants and Their Fuel as Terrorist
Targets, by D.M. Chaplin and eighteen co-authors, in Science 297, pp. 997-998,
2002. In a later response, Richard Gar-win claimed that the authors were
downplaying the risks, which had been treated more seriously in a National
Academy of Sciences report. [See also Science 299, pp. 201-203, (2OO3)J
48 ". . . he was in charge of ..." Biohazard, by Ken Alibek, with Stephen
Handelman, Random House, New York, (1999).
48 "The knowledge and techniques ..." Fred Ikle, March 1997, cited in The
Shield of Achilles, by Philip Bobbitt, Penguin, NY and London (2002).
50 ". .. several scenarios were explored ..." The Jason study of bio-
logical threat was summarised in an article by Steven Koonin, provost of the
California Institute of Technology and chairman of the Jason group, in Engineering
and Science. 64(3-4] (2001).
51 "... simulated a covert smallpox attack ..." The Dark Winter ex-
ercise was carried out by the Johns Hopkins Center for Civilian Biodefense
Strategies, in collaboration with the Center for Strategic and Internationa] Studies
(CSIS), the Analytic Services (ANSER) Institute for Homeland Security, and the
Oklahoma National Memorial Institute for the Prevention of Terrorism. 54
"According to a report." The report is Making the Nation Safer:
194 Notes to Pages 54-59
The Role of Science and Technology in Countering Terrorism, National
Academy Press (2002).
54 "It would be interesting ..." George Poste, in Prospect (May
2002).
55 "... had assembled a polio virus,.. . " J. Cello, A.V Paul, and E.
Wimmer, Science 207, p. 1016 (2002).
56 ".. . more effectively than natural mutations." A technique used by
a US company called Morphotek involves increasing the mutation rate by
inserting into animals, plants, or bacteria a gene called PMS2-134, a defective
version of a gene responsible for repairing DNA.
56 "... sequenced the human genome ..." Craig Venter's project has
been widely reported, for instance by Clive Cookson in Financial Times,
September 30, 2002.
57 "... risks stemming from error ..." The paper reporting the ex-
periments by Ron Jackson and Ian Ramshaw was published in the Journal of
Virology (February 2001).
58 "... even animals that had been previously vaccinated." In The De-
mon in the Freezer (Random House, 2002) Richard Preston reports
experiments by Mark Buller and colleagues at the St. Louis School of Medicine that
attempted to reproduce the Australian results. They got concurrent results, except
that some mice that had been recently vaccinated retained their immunity against
the modified mousepox virus.
58 "grey goo scenario" Engines of Creation, by Eric Drexler, Anchor
Boob, NY (1986).
59 ". . . biovorous replicators." There are some limits on the viru-
lence and speed of a takeover, but these are very crude and far from
reassuring. Robert A. Freitas, in a paper entitled "Some limits to global ecophagy
by biovorous nanoreplicators," concludes that the replication time could be as short
as one hundred seconds.
59 ". .. self-destruct 'naturally.'" Another riposte is that an organism that
succeeds in evolutionary terms plainly must not despoil its habitat completely, but
must instead maintain a symbiosis with it-
Notes to Pages 63-73
195
Chapter 5
63 "... designing web pages ..." The content of the now-defunct
Heaven's Gate cult website is now archived at http://www.wave.
net/upg/gate/heavensgate.html.
64 ". . . cyber-community of the likeminded." republic.com, by Cass
Susstein, published by Princeton University Press in 2001.
65 ". . . Millenarian believers." A series of books depicting the apoca-
lyptic era—the Left Behind series—has topped bestseller lists in the US.
66". .. surveillance might be the least..." The Transparent Society, by
David Brin, Addison-Wesley, NY (1998).
67 "... through films and TV news reports." According to a survey by the
Economist (December 20/27 2°o2 issue), more than two billion people in the
developing world have access to satellite television. Although locally produced
programmes are increasingly favoured, the most popular Western programme in
several countries (including, for instance, Iran) is "Baywatch." '. . . mood-altering
medications . . ." Our Posthuman Future, by Francis Fukuyama, Farrar, Strauss and
Giroux (New York) and Profile Books, London (2002).
69 "If we can alter people's desire .. ." Steve Bloom's article is in the October
10, 2002, issue of New Scientist.
'. .. form of mind control..." Beyond Freedom and Dignity, by B.F. Skinner
Bantam/Vintage (1971).
"... mentally abnormal human beings ..." Philip K. Dick. The story for
Minority Report is in his collection of short stories. 71 "ever more tightly linked ..."
Clock of the Long Now, by Stewart Brand, BasicBooks, NY, Orion Books, London
(1999).
Chapter 6
a series of 'long bets.'" The long bets were published in the
Maɭ 20Ɉ2 issue of Wired.
... whether such a theory even exists." See further discussion of fundamental
theories in Chapter 11.
68
70
196
Notes to Pages 74-81
74 ". . . to witness the outcome." Steven Austad and Jay Olshansky have a
bet on this subject with a stake such that the heirs of the winner may, in 2150,
receive as much as five hundred million dollars.
74 "... introduction of new drugs .. ." "The Hidden Cost of Saying
No," by Freeman Dyson appeared in the Bulletin of the Atomic Scientists,
July 1975, and is reprinted in Imagined Worlds, Penguin (1985).
75 ". . . research just the way it led me." The Island of Dr. Moreau, by
H.G. Wells, first published in 1896.
75 "declaration put forward in 1975 . . ." Asilomar declaration. See
discussion in H.F. Jutson's The Eighth Day of Creation (1979).
76 ". . . attempt at self-regulation . .." The retrospective views of sev-
eral Asilomar participants are reported in "Reconsidering Asilomar," The
Scientist I4[y]:i5 (April 3, 2000).
78 "The views of scientists should not have special weight. ..." There
are two issues, however, where specialists should be heeded: First, they are
best placed to judge whether or not a problem is soluble. Some problems, though
plainly important, are not yet ripe for a frontal attack, so it is no good throwing
money at them. President Nixon's initiative for a "war on cancer" was premature.
Untar-geted fundamental research was a better bet at that time. Second, when
scientists argue that undirected "blue skies" research can be the most productive,
this is not just because they prefer to be free to follow where curiosity leads them.
Even from a hard-nosed practical perspective this can be true: thirty years after
Nixon's programme, a main challenge in cancer research is still the basic one of
understanding cell division at the molecular level.
79 ". . . they are now used in digital cameras." There has been an in-
teresting shift between the 1970s and today. The cutting-edge instruments
used to be developed by the military, and were then adapted for scientific use. Now,
the mass market for consumer electronics (digital cameras, computer-game
software, and consoles) often sets the state of the art. 81 "... clone his elderly dog."
The donor, John Sparling, founder or
Notes to Pages 83-94
197
84
the University of Phoenix didn't get his replacement dog, though the research
group cloned a cat for the first time in March 2002.
83 ". . . an open attitude with regard to students." This openness
plainly should not extend to those who had no intention of gaining education,
but might masquerade as students simply to gain access to pathogens in university
laboratories.
84 "claimed to have generated nuclear ..." The cold fusion episode is
recounted in Too Hot to Handle, by Frank Close, Princeton University Press
1991.
".. . investigating a puzzling effect..." The Taleyarkhan paper is in Science
295, 1868 (2002).
85 ".. . no impediment to openness." Openness would not guarantee
wide and effective scrutiny if the scientific evidence came from some
enormous (and perhaps unique) facility, for instance, a spacecraft or a huge particle
accelerator. In such cases the main safeguard has to come from internal quality
control within the research group, which is likely to be large and intellectually di-
verse in these cases.
86 "in favour of 'going slow.'" Bill Joy, "Why the Future doesn't need us,"
was the cover article in the April 2000 issue of Wired.
Chapter 7
89 ". . . named Shoemaker-Levy after its discoverers." The comet was
discovered by Eugene Shoemaker, an expert on lunar and planetary studies; his
wife, Carolyn; and David Levy, an astronomer based in Arizona. In 1993 the comet
passed close to Jupiter, and the tidal effect of the planet's gravity tore it apart, into
about twenty pieces. It was possible to calculate that the fragments would actually
crash into Jupiter sixteen months later.
93 "It is a minor risk, .. ." Report on the Hazard of Near Earth Objects,
prepared for the UK government by a committee chaired by Dr. Harry
Atkinson.
94 "... a Tunguska-type event wipes out Northern Italy . . ." Ren-
dezvous with Rama, by Arthur C. Clarke (1972).
198 Notes to Pages 94-105
94 '"Spaceguard'-type projects ..." The relevant NASA report is at
http://impact.arc.nasa.gov/reports/spaceguard/index.html.
94 ". . . to divert the trajectory ..." As Carl Sagan noted, if it became
feasible to change the orbits of asteroids, the technology could be used to
divert them towards Earth rather than away from it, greatly increasing the natural
"baseline" impact rate and turning asteroids into weapons, or instruments of global
suicide.
95 "The Torino number assigned ..." The Torino scale is described
on http://impact.arc.nasa.gov/torino/.
96 "... a more refined index ..." The Palermo scale was proposed in
a paper by S.R. Chesley, P.W. Chodas, A. Milani, G.B. Valsecchi, and D.K.
Yeomans, Icarus 159, 423-432 (2002).
Chapter 8
99 "The totality of life. . . " The Future of Life, by E.O. Wilson,
Knopf, New York (2002). 101 "We are burning the books ..." Robert May,
Current Science 82,
1325(2002).
101 "... a Library of Life . . ." Gregory Benford's proposal is described in his
book Deep Time.
102 "... 'footprint' needed to support each person . .." The "footprint"
concept is discussed in the WWF "Living Planet Report" at http://www.panda.org.
105 "Almost ten percent. . ." These figures come from a recent report by
NMG-Levy, a South African labour relations organisation.
105 ". .. other calamitous 'natural' plagues . . ." Paul W. Erwald in The Next
Fifty Years, Vintage Paperbacks (2002), John Brockman, ed., p. 289.
105 "... from decades to hundreds of millions of years." Five hundred million
years ago, there was twenty times more carbon dioxide in the atmosphere than there
is today: the greenhouse effect was then far stronger. But the average temperature
was not substantially higher in that era, because the Sun was intrinsically
Notes to Pages 108-1II 199
fainter. The carbon dioxide started to fall when plants colonised the land,
consuming this gas as the raw material for their photo-synthetic growth. The
gradual brightening of the Sun, a well-understood consequence of the way stars
change as they get older, has counteracted the diminishing greenhouse effect, with
the consequence that the mean global temperature has not changed much. There
have however been fluctuations, between glacial and interglacial periods, of as
much as ten degrees (centigrade) from the average value. Fifty million years ago, in
the early Eocene geological era, there was still three times as much carbon dioxide
in the atmosphere as there is today. There is fossil evidence for mangrove swamps
and tropical forests in southern England at that time; the local temperature was then
about fifteen degrees higher than it is now (though this was partly due to a shift in
the continents and in Earth's spin axis, which placed England nearer the equator)
108 ". .. that trap the heat." This effect makes the Earth thirty five degrees
hotter than it would otherwise have been. The key question is how many extra
degrees of heating will be induced by human activities during this century.
109 "The anti-gloom environmental propagandist..." The scientific issues
regarding global warming are comprehensively discussed in the various reports of
the Intergovernmental Panel on Climate Change (IPCC), on http://www.ipcc.ch.
in "... 'conveyor-belt' flow pattern ..." A clear discussion of the "conveyor
belt" concept is in W.S. Broecker, "What If the Conveyor Were to Shut Down?
Reflections on a Possible Outcome of the Great Global Experiment," GSA Today
9(1): 1-7 (January 1999). He notes that there have been sudden coolings in the past
that if replicated, would transform Ireland's climate into that of Spitsbergen, turn
Scandinavian forests into tundra, and freeze the Baltic Sea all the year round. He
adds, however, that if there were a four- to five-degree warming before a human-
induced "flip" occurred, the outcome, though still unpredictable, would be unlikely
to be so extreme.
200 Notes to Pages 111-120
in "... the next 'flip' much more imminent." The Skeptical Environmentalist,
by Bjorn Lomberg, Cambridge University Press (2001).
in "Earth would need to be substantially hotter than it actually is . .." Such a
runaway could occur if the carbon dioxide level rose anywhere near to what it was
500 million years ago, the Sun being several percent brighter now than it was then.
But the projected rise in carbon dioxide induced by human activities amounts to no
more than a doubling—small compared to the twenty-fold changes that have
occurred on geological timescales. In the natural course of events, the gradually-
brightening Sun could trigger a runaway greenhouse effect due to evaporation from
the oceans perhaps a billion years from now (even with present carbon dioxide
levels). This could destroy land-based life far sooner than the more violent
convulsions that accompany the Sun's death-throes 6 or 7 billion years hence.
Greenhouse warming is even more drastic on the torrid planet Venus.
112 ". . . Charles, Prince of Wales ..." He was lecturing at Cambridge
University in 1994, at the inauguration of a Global Security Programme at the
University.
Chapter 9
116 ". . . the "precautionary principle." There is a huge literature on this
subject. See, for instance, Rethinking Risk and the Precautionary Principle, edited
by Julian Morris, Butterworth-Heinemann (2000).
117 "Edward Teller contemplated the scenario ..." Memoirs: A Twentieth
Century Journey in Science and Politics, by Edward Teller, Perseus, p. 201 (2001).
117 "... a Los Alamos report." E. Konopinski, C. Marvin, and E. Teller,
Ignition of the Atmosphere with Nuclear Bombs, Los Alamos Report. Until 2001
this was available on the Los Alamos website.
120 ". . . an experiment at Brookhaven . . ." COSM, by Greg Benford, Avon
Eos, NY (1998).
120 "... spatial dimensions beyond our usual three ..." See the comments on
such theories in Chapter 11.
Notes to Pages 120-135
120 ". . . scientist produces a new form of ice . . ." Cat's Cradle, by Kurt
Vbnnegut, first published in 1963; available in e-version from Rosetta Books.
122 "Hut and I realised...." Our paper was published as P. Hut and M.J.
Rees, "How stable is our vacuum?" in Nature 302, 508-509 (1983).
123 "... asked a group of experts..." The Brookhaven report, entitled
"Review of Speculative 'Disaster Scenarios' at RHIC," was published as R.L. Jaffe,
W. Busza, J. Sandweiss, and F. Wilczek Reviews of Modern Physics 72, 1125-11-
37 (2000).
124 ". . . summarised the situation like this:" The quotation is from S.L.
Glashow and R. Wilson, Nature 402, 596 (1999).
125 "... a parallel effort..." The work of the CERN-based scientists A. Dar,
A. de Rujula, and U. Heinz appeared as a paper entitled "Will Relativistic Heavy
Ion Colliders Destroy our Planet?" in Phys. Lett. ȼ 470, 142-148 (1999).
126 "... extinction cannot be felt. . ."Jonathan Schell in The Fate of the
Earth, Knopf, New York (1982), pp. 171-172.
127 "... lack of candour in discussing.. . "Francesco Calogero's article
"Might a Laboratory Experiment Now being Planned Destroy the Planet Earth?" is
in Interdisciplinary Science Reviews 23, 191-202 (2000).
128 "... personal assessment of what was at stake." As I have emphasised in
Chapter 3, we seem to have actually been exposed to a higher risk than most people
realised—higher, I would guess, than any but the most fervent anti-Communists
would have knowingly accepted.
131 ".. . what constitutes an acceptable risk..." Adrian Kent, "A critical look
at catastrophe risk assessment," Risk (in press); preprint available as hep-
ph/0009204.
Chapter 10
*35 "... friend and colleague Brandon Carter." Carter's paper was published
as "The anthropic principle and its implications for biological evolution," Phil
Trans R-SocA 310, 347.
202 Notes to Pages 136-144
136 "This Doomsday argument..." The most thorough critique of this line of
argument is in Anthropic Bias: Observation Selection Effects in Science and
Philosophy, by Nick Bostrom, Routledge, New York (2002). Another reference is
C. Caves, Contemporary Physics, 41, 143-153 (2000).
138 "An even simpler argument was used . . ." J. Richard Gott III,
Implications of the Copernican principle for our future prospects, Nature 363, 315
(1993) and his book Time Travel in Einstein's Universe, Houghton Mifflin, New
York, (2001).
139 ".. . the Canadian philosopher John Leslie ..." This argument is presented
in Leslie's book The End of the World: The Science and Ethics of Human
Extinction, Routledge, London (1996) (new edition 2000), which has a
comprehensive account of hazards and the Doomsday argument. The author, a
philosopher, brings zest to the gloomiest of themes. Further references to the
Doomsday argument are given by Bostrom in his book cited earlier.
Chapter 11
141 ".. .John Horgan has claimed the latter ..." Horgan's book The End of
Science was published by Addison Wesley, NY, in 1996. An antidote is What
Remains to be Discovered, by John Maddox, Free Press, New York and London
(1999). I
142 "No matter how much we learn . .." The quotation, a response to 1 a
question by Heinz Pagels, is from A Memoir, by Isaac Asimov.
144 ".. . the quantum theory." Quantum theory wasn't the outcome of a single
brilliant mind. Key precursor ideas were "in the air" in the 1920s, and the theory
was pioneered by a remarkable cohort of young theorists, led by Erwin
Schrodinger, Werner Heisen-berg, and Paul Dirac.
144 "It is a tribute .. ." The quotation is from Stephen Hawking's A Brief
History of Time, Bantam 1988.
144 "This theory is now confirmed ..." As soon as the theory was proposed,
Einstein realised that it explained some mysteries about the orbit of the planet
Mercury. It was further confirmed
Notes to Pages 145-149
in 1919 by Arthur Eddington (one of my predecessors at Cambridge), who
with colleagues measured how gravity deflected light rays passing near the Sun
during a total eclipse. 145 ". . . limit to how precisely any clock can ever subdivide
time." Even though there is as yet no theory of quantum gravity, the scales on
which Einstein's theory must break down can be readily estimated. For example,
the theory cannot consistently describe a black hole so small that its radius is less
than the uncertainty in its position implied by Heisenberg's relation. This gives a
minimum length of about 10 33 cms. The minimum quantum of time, known as the
Planck time, would be this length divided by the speed of light, about 3 x io^44
seconds.
145 "... a challenge for the twenty-first." This conceptual gap actually did not
impede the huge twentieth-century advances in our understanding of the physical
world, from atoms to galaxies. This is because most phenomena involve either
quantum effects or gravity, but not both. Gravity is negligible in the micro world of
atoms and molecules, where quantum effects are crucial. Conversely, quantum
uncertainty can be ignored in the celestial realm, where gravity holds sway: planets,
stars, and galaxies are so large that quantum "fuzziness" has no discernible effect
on their smooth motions.
145 "currently the most favoured attempt at a unified theory ..." An
accessible and entertaining summary of string theories and extra dimensions is
Strange Matters: Undiscovered Ideas at the Frontiers of Space and Time, by Tom
Siegfried, Joseph Henry Press (2002). 147 "Perhaps universes could be created. . .
." This suggestion has been discussed by E.H. Fahri and A.H. Guth, (Phys. Lett. ȼ
183, 149 (io87)) and by E.R. Harrison {Q.J. Roy. Ast. Soc. 36, 193 (1995)) amongst
others. :49 "little more chance than a fish." If physicists do discover a unified theory,
it would be the culmination of an intellectual quest that started before Newton and
continued through Einstein and his successors. It would exemplify what the great
physicist Eugene Wigner called "the unreasonable effectiveness of
203
204
Notes to Pages 152-160
mathematics in the physical sciences." Also, if it is achieved by unaided
human intellect, it would reveal that our mental powers can grasp the bedrock of
physical reality, which would actually be a remarkable contingency. 152 "The big
surprises . . ." The quotation is from John Maddox's
book What Remains to be Discovered noted above. 152 "... midway between
atoms and stars." In the prologue to this book I cited Frank Ramsey's personal
perspective on the world: humans, the focus of his curiosity and concern, dominate
the foreground; the stars are shrunk to relative insignificance. Science actually
offers an objective rationale for this viewpoint, a viewpoint that is, of course, not
peculiar to Ramsey, but is shared by almost all of us. Stars are (from a physicist's
perspective) huge masses of glowing gas, squeezed and heated to immense temper-
atures by their own gravity. They are simple because no complex chemistry could
survive the heat and pressure. A living organism, with layer upon layer of
complicated internal chemistry, must therefore be far less massive than a star to
avoid being crushed by gravity.
152 ". . . atoms in each of us." There are 1.3 x io57 nucleons (protons and
neutrons) in the Sun. The square root of this, 3.6 x io'28, corresponds to a mass of
about fifty kilograms, within a factor of two of the mass of a typical human being.
155 ".. . using ever more powerful computers." The absolute theoretical limit
to computer power, far beyond even what nanotech-nology could achieve, has been
discussed by the MIT theorist Seth Lloyd, who considers a computer so compact
that it is on the threshold of becoming a black hole. See his paper "Ultimate
physical limits to computation," Nature 406, 1047-1054 (2000).
Chapter 12
160 "... no techniques sensitive enough to disclose any of these faraway
planets." The most successful current technique is an indirect one that involves
detecting not the planet itself, but the
Notes to Pages 160-164
small wobble in the central star induced by the planet's gravitational pull.
Jupiter-like planets induce motions of meters per second; Earth-like planets induce
motions of merely centimetres per second, too small to be measured. But Earth-
sized planets might reveal themselves in other ways. For example, if such a planet
moved in front of a star, it would reduce its brightness by less than one part in ten
thousand. The best hope of detecting this minuscule dimming would be to use a
telescope in space, where the starlight is unaffected by Earth's atmosphere and
therefore steadier. A planned European space mission called Ed-dington (named
after the famous English astronomer) should be able to detect these transits of
Earth-like planets across bright stars within the next decade.
160 ". . . Terrestrial Planet Finder." The tentatively favoured design—details
are not yet finalised—would comprise four or five telescopes in space, arrayed as
an interferometer in which the light from the star itself cancels out by interference
(the peaks of the lightwaves reaching one telescope neutralising troughs from the
lightwaves reaching the other) and so does not drown out the ultra-faint light from
orbiting bodies.
161 ". . . possible 'twins' of our Earth." It is unclear what fraction of stars
could have such a planet. Most of the planetary systems so far discovered are
surprisingly different from our own solar system. Many contain Jupiter-like planets
on eccentric orbits much closer in than our own Jupiter. These would destabilise
any planet in a near-circular orbit at the "right" distance for its parent star to be an
abode for life. We cannot yet be sure what fraction of planetary systems would
permit a small Earth-like planet. 162 "Donald Brownlee and Peter Ward ..." Their
book Rare Earth is
published by Copernicus, NY (2000).
164 "For all of life's plenitude . . ." The quotation is from Simon Con way
Morris's article in The Far Future Universe, G. Ellis, ed., Templeton Foundation
Press (Philadelphia and London 2002), p. 169. See also Conway Morris's book The
Crucible of Creation, Cambridge University Press (1998).
205 206
Notes to Pages 165-177
165 "... a 'head start' on planets around these ancient stars." The astronomer
Ben Zuckerman suggests (in Mercury, Sept-Oct 2002, pp. 15-21) another reason
why we would expect visits if aliens existed. He points out that any aliens who had
themselves surveyed the Galaxy with instruments like the Terrestrial Planet Finder
would have identified the Earth as a specially interesting planet with an intricate
biosphere long before humans came on the scene, and so had plenty of time to get
here.
165 ".. . UFOs have indeed visited us." We should maybe be thankful to be
left alone. An alien invasion might have the same effect on humanity as Europeans
had on North American Indians and the islands of the South Pacific. Independence
Day may be a truer depiction than ET.
167 "an entire language for interstellar communication, ..." Hans
Freudenthal, Lincos, a Language for Cosmic Intercourse, Springer, Berlin (i960).
Chapter 13
169 "... this picture should be complemented by another one, ..." The Fate of
the Earth, by Jonathan Schell p. 154.
174 ". . . advocated by the maverick engineer Robert Zubrin." The "Mars
direct" strategy is described in The Case for Mars: The Plan to Settle the Red
Planet and Why We Must, by Robert Zubrin with Richard Wagner, Touchstone
(1996).
175 "Two years later ..." The relative positions of Earth and Mars are
optimal once every two years. That is the reason why two years is the natural time
interval between successive launches.
176 ". .. when propulsion systems are more efficient." This same problem
would arise on any habitable planet, because gravity has to be this strong to retain
an atmosphere at a temperature suitable for life.
177 ". . . what kind of novel propulsion systems will prove most promising."
Solar panels can provide low thrust, for an unlimited time, in the inner parts of the
solar system, but in the outer re-
Notes to Pages 177-182
gions sunlight is too weak, and even large and heavy panels yield very low
power. At present, probes into deep space carry ra-dioisotope thermoelectric
generators (RTGs), which yield enough power for radio transmitters and other
such equipment. To provide thrust for propulsion (especially if one requires enough
to shorten journey times to the planets, rather than just midcourse corrections),
some kind of nuclear fission reactor would be needed. This is a reasonable medium-
term prospect. Longer-term and still speculative options include fusion reactors and
even matter-antimatter reactors. 177 "Very thin carbon 'yarns' have already been
made ..." See K.
Jiang, Q. Li, and S. Fan, Nature 419, 801 (2002). 179 ". . . Gerard O'Neill, an
engineering professor at Princeton." O'Neill's ideas were published in the book The
High Frontier, William Murrow, NY (1977), and promoted by an organisation
called the "L5 Society." L5 denotes a position in the Earth-Moon system specially
appropriate for locating a "habitat." G. Benford and G. Zebrowski's anthology
Skylife: Space Habitats in Story and Science collects a set of fictional and scientific
articles on this theme.
180 "Whether human beings will themselves have joined this diaspora . . ."
This is one of Freeman Dyson's favourite themes, first adumbrated in his Bernal
lecture. Indeed J.D Bernal in 1929 had ideas of this kind. A later Dyson reference is
Imagined Worlds, Harvard/Jerusalem lectures (2001).
182 "The tree of life may reach twice ..." Life Evolving: Molecules, Mind and
Meaning, by Christian de Duve, Oxford University Press (2002).
182 "... look forward to a near-infinite future." In the 1960s, Arthur C. Clarke
envisioned the "Long Twilight" after the death of the sun and today's other hot stars
as an era at once majestic and slightly wistful. "It will be a history illuminated only
by the reds and infrareds of dully glowing stars that would be almost invisible to
our eyes; yet the sombre hues of that all-but-eternal universe may be full of colour
and beauty to whatever strange beings
207 Notes to Pages 185-188
have adapted to it. They will know that before them lie, not the "... billions of
years that span the past lives of the stars, but years to be counted literally in
trillions. They will have time enough, in those endless aeons, to attempt all things
and to gather all knowledge. But for all that, they may envy us, basking in the
bright afterglow of creation; for we knew the universe when it was young."
(reprinted in Profiles of the Future, Warner Books, NY (1985))
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